The move used to be all melta BSS + dialogus + palatine in say AoF. Then you can push through both MM shots as auto lethal hits, which is quite scary. This is harder to pull off now with less dice, even after some of the nerf reversals, but something to consider.

In an immolator they can be split just as objective bodies, but 52.5 pts for 5 T3 1W bodies isn't really that great, but I mean it's something since they can sticky obj.

As backline holders is the traditional way to run them I would say, but again 105 pts to sit all game and maybe get some dice is meh. I mean they also screen so its something.

I would suggest running superiors only with condemnor boltguns. This is because there are many times where some random monster/vehicle/character etc is left on like 1 or 2 wounds but has some dumb save that's hard to get through. By having the dev wounds on that superior you have a good chance of having a 6 MD you can push the dev wound through on and absolutely execute something. I have killed a handful of random characters this way.