Youshould trim away all leaves and buds under the screen if your canopy is full. 2-3 weeks into flowering.
Dont top in the middle of flowering..
As far as above the screen is concerned...In scrog id say you should just tie the leaf, stem down, bend it under another or remove it if its blocking light to the buds. Use a rubberband or whatever. Thats the whole point of a scrog. Move longer stems to the outside or keep em against the outer wall so they dont block light to others.
Lollipoping is more effective in a high density sog where you have 3-6plants/sqft. if you have too many plants under your screen, you might have no choice but to lollipop.
In scrog you have the option of bending them out of the way. If that doesnt work, trim.