Hi,
So you like your
HQs then

. I don't have my codex with me so I'm not 100% on the points and you'll have to remind me what the harp does, and gauntlet of fire for that matter (I've leant my codex to a friend so he can try out my cron army).
From the list you've posted I'm guessing you like your necrons quite shooty.
If you're running the D. Lord with the wraiths you might want to take mind shackle scarabs instead of the arrow. It'll give you a little more synergy.
I will guess your necron lord is with the 19 man warrior blob. You won't need the weave with him, or
MSS or possibly the phase shifter. Just hide him at the back of the unit. You don't want these guys in
CC so drop any
CC upgrades.
Swap your harbinger for the one with the chronometron and attach him to your overlord. There is nothing worse than your tachyon arrow missing and not having a re-roll.
Drop the 5 immortal squad and upgrade your 5 warriors in an ark to 10. There isn't much that can stand up to 30 gauss flayer shots in rapid fire range and the AV13 with 4 hull points will keep them going for a good while. Also it gets a jink save as a skimmer I believe.
You should have some points left over (if my memory and maths is correct) you can use this for more immortals in the scythe, or my recommendation, another wraith.
If I have got your tactics wrong, or you'd like to play crons another way let me know and we can adjust your list from there.