The only advice I can give is use overhangs and hug the walls along the cliff edges of the map.
Also, try to do as the Sirens do, and find a lower-tier path through some of the map.
Basically, the more of the damn thing’s shots you can get to overshoot you and drop down a well, the better.
Consider yourself lucky. As you know, I’m an outspoken fan of this game - and I constantly argue for making it more difficult - but Lairs suck so much that I actively let them mature into Citadels rather than have to engage with them.
However, as I said in my Lairs vs Citadels post, I don’t want to get rid of them - I just think they should be the other way round. Lairs are the hardest Missions in the game, and having them as a mid-level tier when Citadels are so piss-easy just makes a mockery of the Panda-Base progression.