Blank off or grind off engine/gearbox mounts when powder coating the frame?

I’m sending my frame, swingarm, and bits to the powder coater next week and have blanked off the mounting holes with nuts & bolts per Old Britt’s tech note. I’m found the suggested bolts and washers listed in the note are not exact diameters resulting in mis-aligned washers that float around the hole, and I suspect they will either leave depressed leave rings around many of the holes after it’s been painted, or worse, result in some of the mounting washers covering the powder if the washer…