Gengar question

I have 9 Gengars that I can power up or TM.
As you can see, my highest CP Gengars all have Sludge Bomb. Not a great move in the current meta.

IVs are ATT/DEF/STA.
1: CP 2087 IV 73 (14/08/12) Hex/Sludge Bomb
I only evolved this one because her immediate CP would be above 2000.
2: CP 1622 IV 89 (15/10/15) Sucker Punch/Sludge Bomb
3: CP 1603 IV 82 (12/11/14) Shadow Claw/Sludge Bomb
4: CP 1588 IV 91 (15/12/14) Sucker Punch/Sludge Bomb
5: CP 1481 IV 93 (15/14/13) Hex/Focus Blast
6: CP 1460 IV 84 (15/13/10) Sucker Punch/Dark Pulse
7: CP 1260 IV 89 (exact combination unknown) Hex/Sludge Bomb
I have 2 more with Hex/Shadow Ball, but CP below 700.
Should I TM Focus Blast for my 93% one, Sludge Bomb for any of them, or power up the 2 Hex/Shadow Ball ones?
I have 12 Gastly candies and 70,000 dust. I will have to use rare candies to power them up, as Gastly is rare in my area.