Looking great dread, nice to see you started the tucking! Don't worry too much about a snapped stem, it will happen occasionally in a scrog. It wasn't until my 4th attempt I managed to get through the whole grow without a snapped main stem
. As noods said, they're easier to train when they're dry so if possible do the major tucking just before watering and never directly after watering. Another thing I tried is to pre-bend them, so before pulling the main shoot under, tie it down to the top of the screen to straighten out the 90 degree bend and leave it like that for a few hours then pull it all the way under. That way you're not bending more than 90 degrees at a time. I found that helpful in avoiding snapped stems.
You're probably right about a rigid screen as opposed to a net. I often find myself pulling on the net to make it easier to get the plant under.

You're probably right about a rigid screen as opposed to a net. I often find myself pulling on the net to make it easier to get the plant under.