I use treants for my troops, though they die in like less than a second... lol
I'm a bit out of touch with the older ID's as its been awhile since I've last done them.
However, the last time I cleared up to ID4-10, I used PD Cup Druid Nick DD Santa. I had no problems at all.
Drop placement and spell placement are critical, so I recommend checking out the Insane Dungeon guides in the "guides" section of the forum.
You can drop 4-8 Copters before your Heroes, and this sometimes helps. Start from the bottom right if the bottom left is not working, or vice versa. The only troops you should be using for dungeons are Copters and Guardians.
Team: Mike, PD, Cupid, HBK, LN, and Grimfiend.
Future: Focus on Espirita. SM might be helpful on a dungeon or 3, but wait until you get stuck with Espirita (unlikely).
With your crew at 161e and Mike and Espirita at 9/10, you should be able to conquer 5-10.