FB3 Quickshow / Kvant Spectrum beam target help

Good morning all, hope you are well

I have a couple of lasers that I master/slave together, one Kvant and the other is an older unit that a friend who knows far more than me rebuilt with some newer laser modules. Both work very nicely.

I'm a hobbyist and relatively new to the scene, but have some friends in the club/DJ world who run club nights and I've provided my services a few times.

The lasers are run using FB3 / Quickshow.

I have a night running tomorrow but the space has some challenges. Height wise I've easily got 2.5-3m of height above the audiences heads so all good there. The room is oblong in shape, but not particularly wide.

I will not be crowd scanning, so set the XY slider to the left to keep all projections horizontal so they do not project down towards the crowd. However, some of the cues (hot beams etc) still throw the light beams UP rather than keeping them flat/horizontal so that they hit the ceiling/roof. I am concerned about beams potentially bouncing off the ceiling into peoples fields of view. The ceiling has a matt finish, but there is a wooden varnished balustrade about two feet from top to bottom that runs around the perimeter of the room under the ceiling (the ceiling is false/suspended and splits the room height in half, it is an old church that has been turned into a nightclub)

Is there any way to set ALL projections to only hit a certain area?

Apologies for the lack of terminology or correct explanations, I hope that makes sense? What I am trying to achieve in essence is for anything coming out of the projectors to only go to certain area on the rear wall of the room and I would like to know if anything can be set in Quickshow to do this?

Maybe overthinking it but better safe than sorry

Thanks in advance, Si