Dr. Serling wrote:
If your going for a mantleseer, don't take the spirit stone. Things that ignore cover or armor will absolutely ruin your day without that 4++. The stone has uses, but only if your going for a 2 cost power. This usually means telepathy, but fortune and (sometimes) eldritch storm from runes of fate can be useful. Some games you won't hit any 2 cost power(you will always hit a 2 cost if you roll 3 times in fate, but most of the powers suck sans fortune, doom and sometimes storm). Runes of witnessing is OK, but certainly not required. For your best all purpose seer, always roll once on runes of fate. Keep doom or fortune(maybe storm if situation justifies) and take guide if you hit anything else. Once you take guide, go to divination. Forwarning, misfortune, and maybe precognition are good here, once you get stuck with prescience go to telepathy. Basically everything in telepathy is good, it just depends on what you need. If you want, you can go to telepathy before divination.

Fast shot is required for the avatar, but marksman's eye is too expensive and won't accomplish the job you want. Most force weapons, power fists etc are on characters who can look out sir! the hit, or are in a unit like terminators where everybody has them. Since they are on characters, better to take disarming strike. If you find yourself agaisnt them, the odds are in your favor to disarm your opponent. Most enemy characters will die to the avatar in solo combat, but it helps if your up against something nasty like a wolf lord or any form of libby/sorcerer.

For 3 man bike teams, cannons are really a matter of taste. I take them to fill points, but it is rare my bikes even shoot. Maybe 1 out of 5 games I actually use my 3 man bikes to shoot, so it really depends. The cannon is fun if you can dakka rear armor or finish off a small squad, but I assume your hiding in reserves, so expect those points to sit around doing nothing for a while. Its really your call. If you go with a 6+squad, always take 2 cannons and be ready to shoot them.

I am generally not a fan of the EML on guardians(or anywhere), but if you really want the range, I can see the arguement. Orks are usually mobbed for fearless and marines have decent leadership, but when you pin a unit it can be very effective. I personally like lances or scatter lasers on guardians, but the shorter range can be an issue. Just make sure to kite max range and stay out of range of return fire.

Avengers are fine on foot, probably don't need the shimmershield since your not expecting drakes, but YMMV.

Serpent is fine. Taking scorpions just to infiltriate/outflank with a lone tank is risky(it will draw AT fire and could be assaulted). The exarch is dead lethal, but if you just want the outflank/infiltriate, again wasted points. It means turn 4 minimum before you could see assault. I would keep the serpent back and load it with guardians/avengers, or fire dragons for AT.

If your going to use the EML's on the vypers, again range is the name of the game. Imperium heavy fire usually comes in 4' range, meaning missiles can hit you back, as well as auto/lascannons. However, the imperium carries these on foot, or on slow heavy tanks. Move 12" every turn to stay out of range, or if you get in range, make sure you kill that predator, those long fangs, lootas, etc. Since your playing the range game, drop the shuricannon. Vypers should kite distance and pick off easy targets. If you find yourself close enough to fire the cannon, bolters can rapid fire you down. The catapults are fine for last ditch efforts. Holo fields are also expensive on such a fragile model. If you dropped them, you could get another vyper. Best defense is not being hit, and with speed/mobility, should be doable.

The lone walker puts out high amounts of dakka, but is an easy target. Saturates more Av10 with the vypers, but without buddies it will probably die. One thing you could do is take a scatter/shuricannon and outflank, showing up and popping rear armor, or messing up a backfield squad. A bit cheaper, and gaurenteed to get a good volley off. Scatter/starcannon is also good if you want the Ap2. Dropping the walker for a nightspinner or prism would be another solid choice.

Wraithlords and the Avatar provide a nice MC saturation, and very agressive threat. Without tanks they will draw AT fire. Use lances on the advance, then flame anything that gets close. I always take swords with extra points, just in case they get stuck in CC.

 Dr. Serling wrote:
The second list looks a lot better. The big thing that sticks out is the jetbikes. Always take them in multiples of 3 to unlock the second cannon. Make 2 squads of six and 1 squad of 3. Then get a second cannon in each six man team.

By hidden power fists or other stuff, I assume your talking about grey hunters. Power fists, mark of the wulfen, and then terminators of any army can be trouble. Generally better to avoid the unit or shoot em to the point the Avatar can sweep before they strike back. Marksman's eye and runes of witnessing would buy the cannons and change(swords for the lords, crushing blow on the avatar, etc). Not that the runes are bad either, but cannons are better worth it.

I am much more a fan of the scatter/shuri or dual shuri vyper build. Cheap, fast, and deadly. Try playing around with 3 seperate units instead of a single squad.

 Dr. Serling wrote:
The second list looks a lot better. The big thing that sticks out is the jetbikes. Always take them in multiples of 3 to unlock the second cannon. Make 2 squads of six and 1 squad of 3. Then get a second cannon in each six man team.

By hidden power fists or other stuff, I assume your talking about grey hunters. Power fists, mark of the wulfen, and then terminators of any army can be trouble. Generally better to avoid the unit or shoot em to the point the Avatar can sweep before they strike back. Marksman's eye and runes of witnessing would buy the cannons and change(swords for the lords, crushing blow on the avatar, etc). Not that the runes are bad either, but cannons are better worth it.

I am much more a fan of the scatter/shuri or dual shuri vyper build. Cheap, fast, and deadly. Try playing around with 3 seperate units instead of a single squad.