5, 4, or 2?

Zyrook

My Roster

So I'm at an odd spot. I've got plenty of 4*s champed, most of the good ones at least, and 8 fully covered. So far the RNG gods have not smiled on my and my OML is no where near useful (3/0/0), but I just pulled my 5th cover for Spider Man (3/2/0) which puts his cap at 330. I also have 5 unchamped 2*s.

So what I'm wondering is where my ISO should go now? Thoughts? Should I go and bring a few more 2*s up for farming? I have 3 fully covered, the other two being recently rebooted. Or is Back in Black Spider Man worth raising? I've hardly touched 5*s, so I'm pretty clueless there. Or should I keep raising up 4*s? The 8 I have covers for are:
Fury
Elektra
Ghost Rider
Invisible Woman
Miles Morales
Prof X
Sam Wilson
Thing
I'm considering IW after her recent buff, Miles for his AP gen, or Elektra just to be a pain. I've heard good things about Thing, but was unimpressed with him when forced to use him recently, Sam I used to use with Ant and Switch but find myself fielding full 4* teams these days. Fury seems due for an update though.

El Zoof

My advice would be champ your two stars. The others aren't going away and aren't in a position where you'll lose anything by waiting. Sure, it's the boring answer, but raising people who aren't going to be competitive and will give you harder targets gives me the heebie jeebies.

CT1888

2*s and work the farm. I'm not in 5* land yet, but wouldn't be considering iso into that pair at the moment in your position.

For what it's worth, my thinking is I'd like to have 1 or two boosted 4*s per week, so I'm looking at where I have gaps in the weekly listing and trying to fill them. Invisible Woman might be next for me.
Champed Thing recently, and while he's not the most exciting to play, nice big health pool always put me off attacking him before. Working well with Teen Jean for me just now.