Let me offer some advice straight from BOP about the 1-piece gasket.

But first I have to assume that these measurements you speak of above are with the pan and gasket just sitting on the block (upside down) or is this with the bolts in and snugged down????

Anyway - BOP says glue the rear section of the 1-piece gasket to the oil pan using super weatherstrip adhesive. The curved rear section is the only part without the metal reinforcement built in. I found that I had to carry the glue past the 1st back corner bolt holes. Painters tape to hold the rest of the gasket to the pan was also helpful.

Then snug the pan to the engine with the bolts (snug, NOT fully torqued) and wait 24 hours for the glue to dry.

Then remove the bolts, apply a dab of silicone in the rear corners where the rear bearing cap thrust block meets the pan (where the oil pan seals to) and then bolt the pan on and torque down the bolts.