Definitely expect the metal to warp and crack from the high heat. That type of steel isn't made for heating over and over at those temps.

Even with all the insulation it will translate through and damage it. Good luck though.
It will work for a little while so there's always that.

I have known people to use propane bottle and air bottle forges for years with this setup without issue. Thats why I settled on this setup. My Father is also a metal worker and he actually went to school for this shit so I think I am safe for a while.