Keep in mind these soild core doors will sag over time and cause building problems. I built a 2X4 frame for my 3 tables to help with the sag problem. It is made slightly smaller than the 3' 0 x 7'0 doors so I have a little overhang, about 1 1/2 to 2" smaller with joist 2' OC. I also ran the 2Xs over the joiner to insure a perfectly straight edge and use 2x or 4x legs. A leg dead center also helps with support. I put 3/8 t-nut and bolts in the leg bottoms so they are adjustable up and down with an open end wrench. Once it's in place I use my 4' level to completely level the enitre table left to right, front to back and corner to corner.

I build on 1/2" sheetrock or ceiling tile so pins go in easily. Masonite is good for a table protector but it won't take pins. Drywall is VERY corrosive so don't leave pins in too long.

Rick