I’ve currently got 6 covers for both xforce and Thor modern so my question is, is it better to aim to max out Thor first (considering he only costs 1250hp per ability) or just grind for xforce?
Thoughts?
Oh and currently I have only 2 maxed 3* chars and one of them is wolvie (patch)
Do you have 4 in X-Force black? If so, go ahead and buy the final black and level him; otherwise, wait until you have more covers.
I never bought more than 2 covers for any character (which was The Hood in my case).
I only have 1 in black, 2 in green and 3 in yellow 
Level Thor then. It’ll be easier to get progression/placement rewards for the rest of your XForce covers with a covered and leveled Thor.
You should also concentrate on other top 3* characters that work well with Thor. Once you have one or two good combos to use for PVP you can worry about putting resources in to XForce.