Polygel beginner questions

I want to start using polygel to do my nails. I have watched a ton of videos on youtube and have a few questions. I have seen three ways that polygel has been done: 1) using dual forms/nails tips where the tips are popped off, 2) using nail tips that stay on, and 3) sculpting on paper forms. I am not interested in method 3. Questions:

1. When using the polygel as glue inside the nail tip, how thick do I make it? I know it is supposed to be thinner near the cuticle, but how thick in the other areas?

2. On one video a person who had flat nails used tips with an apex and just made the polygel a little thicker in the apex area. Would this cause it not to cure properly?

3. Is it easier to avoid bubbles with polygel than with nail glue? I worry that I won't do a good enough application and will get the greenies.

Thank you.