Your list needs some work, your wasting 40 points on the Lascannons on your Lemans. You are going to be shooting at infantry, and the
LC shot is gonna kill half a guy every turn? For 20 points? Give them
HB, and don't get the sponsons.
Also, make sure there is no room behind your tanks so he does not come in behind your lines with Snikrot (which he probably will).
More Flamma (
lol) is a very good thing against orks.
Your lone Vendetta is going to be a BIG target for his Lootas, which he WILL have if he has any brains. Which I'm sure he does.
Its personal choice for
PWs in your blob or not, I would keep them because what happens when a mob of Meganobz assaults you? or when a 30 strong mob of 'Ard Boyz charge you? Your gonna want at least a LITTLE staying power with your blobs.
But, Brother T has a point; most likely it will be normal Boyz with a 6+ t-shirt save attacking you, in which case the
PWs will be wasted points.
Your Sentinels aren't doing anything for you that a
HWS couldn't do better (other than Outflank of course). It would serve you better to drop them for more Autocannons in the form of a
HWS.
Stubbers on the Chimeras are wasted points because they are Heavy, and can therefore only shoot when you do not move.. which will maybe one turn in the whole game? Especially if you put them in reserve.
Penal Legion is a no, just because they will get destroyed by the first Boyz mob they come into contact with.
So, after making all of the changes I have mentioned, you have 260 points to spend on good replacements for what you dropped.
Here is my suggestion:
HQ:
CCS 105
MoO, Lascannon, Vox
Troops:
Vets 155
MeltaGun x3, Chimera (
HF/
ML)
Vets 170
PG x3, Chimera (
HF/
ML)
Vets 135
Lascannon,
PG x3
Platoon = 585
PCS Flamer x4, Chimera (
HF/
ML)
Squad
Commissar, Melta Bombs,
GL,
AC,
PW x2
Squad x3
GL,
AC,
PW HWS: Autocannons
SWS: 3 Flamers (In Vendetta)
Fast Attack:
Vendetta = 130
Hellhound = 130
Hellhound = 130
Heavy Support:
LRBT w/
HB = 150
LRBT w/
HB = 150
Manticore = 160
OK, now we can break down how to use this in the most efficient way possible (while still conforming to the theme of your original list).
DO NOT put half of your army in reserve, then he only has to face half of your army at a time, making at infinitely easy for him. Start all of your units normally in your deployment zone.
Bubble Wrap your Lemans and Manticore with your Blob, and make sure there is no room for Snikrot to come in behind you.
Vendetta should be moving back and forth along your table edge, DO NOT suicide the
SWS in because you will lose the Vendetta. Use it as long rage
AT, and as the orks get closer, you can drop your
SWS and flame them, but make sure not to do it too soon, so you can get maximum use out of those 3
TL Lascannons.
Chimeras should all be moving forward turn one. Good strategy is to pop smoke first turn and move them 12 inches up field. Then next turn move your normal 6 and start burning the crap out of the Boyz squads. Make sure to melta any and all vehicles while your up there. Your probably going to lose these squads (because there are only three). But it will do a fair amount of damage and slow down his advance. Unfortunately, that's 6
KPs right there, but then again, Guard are always at that disadvantage.
Move the Hellhounds up with this squad, but keep them a little ways behind, as their range is 24" (plus template) and they do not have to get as close as the Chimeras. They are also fast, so you can kite large boys squads. (Move away so they cannot assault you while burning the hell out of them).
Put your
HWS in behind the Blob, as well as your
CCS and foot Vet squad, and issue an order to the
HWS and another to the
CCS (I'd actually drop the Vox on the Vet squad, because now you have a
HWS to receive the second order). - Keep the vox on the
CCS though, because it can re-roll orders that it gives itself. Both the
HWS and the
CCS should be issued the order 'Bring It Down" to get
TL against vehicles and
MC's. Which is also very useful for the
MoO, because he is now
TL.
Hope that helps. Good luck!
P.S. Green is best
EDIT: Had some point value typos. Derp.