Success! Glaze was at around 70° when I sprayed the mousse. It's a bit hard to see if you glazed it enough, when you don't color the glaze though. No clogging until I stopped spraying (I did leave the gun in the oven at 50°, to warm it up a bit, which might've helped with that.)
I'll post a picture when I've made the real attempt. This was just "faux" mousse to see if it would work. Don't want to waste expensive ingredients in the try outs. 
Edit: for future reference; I used a 1,5mm nozzle.
