Working on prep for my fan hole. Built a frame/hole from some 3/4" and a couple runners that i can screw into the roof "joists". Tomorrow I'll grab some sealant/adhesive, punch a hole up there and stick that thing in.

When I'm cutting that hole, can i just do 4 holes in the corners from below, go up top, draw a line connecting corners, tape off around the cut, then scroll saw, with a metal blade? Liberal sealant all around, place the fan, screw it down, more sealant. That basically it?
Thx,
Mark