I have a desk top that's a 3" thick stilted maple slab that's 6' long, but varies in width from 22" to 18" to 22"

: I used a cheap Ikea desk top, and it worked perfectly

I went to IKEA and got their Gerton desk top, and had to simply drill 4 holes and use 1/2" wood screws to mount it

I made my own custom desk tops.

I put my old desk top on top of

I put my own desk top that I already had on it (70 x 23).