N-DMT, yep you can put a little weed in the ash should help catch the melting crystals, but try to not be stoned before the time, the clearer your head the clearer the visions.
You can use a small bong with room temp water, you will loose a little product, so will need slightly larger doses.
Yep, you can get up and go on with things, you may feel a little mushroomed for a minute or 3 if you bail out, but all good after that.
I sometimes abort launches when it just doesnt get me there fast enough, no biggy, things just look a little trippy for a few minutes, some people even do it open eyed.
What I need to stress is the short duration, my longest voyage has been 15 minutes, but the average for myself and observed is 5 minutes, thats all... I've taken shits that lasted longer.... loose the fear, in fact with the absolute need for control you are displaying, I'm not sure it is the route for you. The best experiences come when you still your inner babbling voice, and just fall into it like a slumber.
I know for a fact 5-meo would bitch slap you.