No 'tricks' needed.
I just did some 16x20s with one-inch border last night. Negative is 51" from the baseboard and the lensboard is 36" from the baseboard. Going by the millimeter markers on the column, the baseboard is at 250mm and the head is at 1305mm (L1840, 300mm lens).
Try setting up your enlarger with those settings and you should be very close to where you want to be.
If it is still not right, post a picture of your setup.
You should be able to do 40" prints in the vertical position with that enlarger. If you can't, its like having a Ferrari and only being able to go 35mph