Hi, not sure if this helps - but - the only way I managed to totally avoid bubbles was to not use the nail trainer glue - I used Creative Gelbond - it is much easier to control and sticks start away - I also found that the supplied nail trainer tips are quite thick and even after reducing the well took much longer to blend than other tips, the amount of dust I manged to produce until I switched to Creative tips was amazing.
I did the Creative Foundation course about a month after I started the Essential course so I used Creative's gelbond and tips with the Dream liquid and powder otherwise I would never have had managed to complete the Essential course, I tried the nail trainer glue again last week and compared to Gelbond and Speedbond it is like trying to stick a tip on with water...
Good luck with the course & happy new year..