Welcome to the forum.
I'd say you should try with 20 mg first, as long as you have enough to dose again later on, I did a sub-breakthrough dose my first time, and it was still pretty amazing.
with 20 mg you might still break through too, if you smoke too much you could black it all out and not remember anything when you come back.
Also, vaporizing can be tricky, I have long since given up on vaporizing, I just dissolve my dmt in acetone and infuse it with sage, it works great for me.
I hope you have a safe hospital trip as well, if you don't mind me asking, what's putting you in the hospital?
If we are all one, we are all alone.