My counter tops have been cut in a precision miter and holes made underneath for the bolts that join the corner together. We did a dry fit and everything joins perfectly. Normally, you would lay down the longest run, then affix the perpendicular run up to it, go underneath the counter at the underside of the cabinet and affix the bolts to tighten together. My problem is the corner cabinet (a lazy susan cabinet) has a finished interior top in the carcass, which means when you look up, you are not seeing the underside of the counter top so you can access it to bolt it together. Must I destroy the interior "lid" of the cabinet top by cutting it open or is there any other way? Help!!!!! This has to go in now!
I am not sure if this is possible in your situation, but when I did mine, I put the top together first, using silicone between the joint, laid the tops upside down and level, then bolted them together. After that 2 helpers and myself set it in place and screwed from under. Hope that helps.