Hi Dudester
Nice looking compact, is it possible for you to post a photo of it from the rear, showing what the sight picture looks like? I'm considering the same or similar setup for my P-01 and I want to see how it looks from the rear before I commit to milling the slide. I think the 75D compact and P-01 slides are the same, but I'm not sure.
I'm familiar with the 507k as I have it on a Sig P365xl, I was considering the Trijicon R06 for the P-01 but that optic may be too large for it.