I took the backseat out of my 92 Tracker 2 door convertible for my ice shanty that I am gonna buy. BUT- if it don't fit, how much weight can you put on the roof? I don't have a rooftop carrier (obviously) but, I was going to bungee it to the rear wheel wells.

PS- Oh yeah, my fish house weighs around 50-60 lbs folded up, and the piece I am concerned about is the back bar that holds the top up (with the buttons on it), don't want to bend it.

that part wont hold crap for weight..  Just strap it to the windsheild support and roll bar   

I carry my Kayaks straped to the roof of my soft top Kick. Combined they probably weigh 80 pounds and I also wratchet strap them down with additional pressure to keep the wind from blowing them around. Not to mention I have stood with a friend (totaling probably 350 pounds) on the "roll/targa bar" with no damage. Just watch putting alot of top weight on her causing excessive body roll.
Zig