Hey and welcome if I haven't said that already in another thread!
Given where the circles on the floor are, there will not be all that much deformation going on, the ones that you have down right now do not look "off", however they are quite rough so it will be more apparent whether you got em right when you clean em up, just remember that they will touch the sides of the containing squares at the center-point of the squares side, from that you should be able to eyeball the placement.
The ceiling tiles can be made quite easy by thinking about the fact that there will be a consistently sized side that runs along the large cross beams you put up, so if you place dots at consistent spaces along one of those beams you can simply trace the line out from your vanishing point and it will line up all your tiles perfectly along the ceiling.
Good luck and welcome again! Keep at it!