You said your gear is bad so dunno the exact stat of it, but of your leveled people could probably go with something like this:

Doompriest (Lead), Kael, Rathalos, Sun Wukong, Uugo

Can always try Rathalos lead as well. Doompriest would help if you are lacking some speed. Rathalos will help you do more damage if you aren't killing the spiderlings.

Wouldn't have a burn, but should be enough damage to control the adds and heal / cleanse your party.

Rhazin and Armiger you can use for Turn Meter control. 

Id also recommend looking into leveling Miscreated Monster.  Provides a massive shield and some Crowd Control in the form of stuns.

how high before using him? I've got him at 40 now but don't have the champs yet to get him to 5.

I'll try this out. I'm still learning about stats, but I do believe they all have "the best I have" gear lol.

tbf ur probs better sticking to st10 due to the drop rates of gear being outa whack there till u can get to st17 or higher (assumeing they havent altered rates)

Dragon 20! Stop everything else:)

I'm up to Dragon 14. Can't remember if I've attempted 15 yet so I'll see how far I can go before posting about THAT :)

New thread + post gear. Honestly you would be surprised at how easy it can be.

Not afraid to ask the dumb questions so here goes:

gear on the champ or gear I have?

Probably some combination of both, but let's start with just the advanced stats screen on the five I'd recommended you use for D20.