Thanks.
Not sure if my method is the best way, but seemed to work.
I leveled them flat on my granite countertop, taped them together with painters tape, filed, checked fit. Did that 5 times and stopped about just right I think.
There is a tiny gap at the receiver when you slide them together, then when you tighten it all up they fit as it shows. I’m not sure if I could get them any better so I quit while the quittens good. Lol. Nice snug fit and most everything lined up except for the top which is normal.