have you tried putting the gelatin and hardener and emulsion on a piece of paper as a test
to see if it fogs or bubbles or streaks &c on the paper ?
is your emulsion fogged because of how + where it is drying ?
the glow from the blow dryer might fog ... and ambient + safe light too...
do you add a little wetting agent / surfactant / something like photo flo to the emulsion so it coats evenly ?
( several coats of the emulsion ) ?
have you tried to coat the canvas as you did before, but put hardener in the fixer or the developer bath rather than in the emulsion itself?
that might also help ... if you put the hardener in the developer it might allow you to put a second coat of gelatin and then 2 coats of emulsion on your canvas to make sure it is coated evenly and dries better.
instead of cascading the developer on the canvas have you tried to use a spray bottle and mist it?
or removing the canvas from the stretchers and see-sawing it in a smaller tray or dammed part of your sink ?
i have never printed on canvas before ... if you were asking about glass or plastic or black-metal or paper i would have a better answer .. sorry..