The holes are exactly 1 inch apart, center to center.
Not sure I follow. The Metro loop is about 1.5 inches measure the center of the send jack to the center of the return jack.
Yeah, I was afraid this might be the case.
As another option, I know Nik from Ceriatone offers a buffered loop board that doesn't have the jacks soldered to the board. The board has 3 holes in it, any of which can be used to mount it on a stand-off, and then you fly some short leads over to the jacks. I actually have one here that I bought for a Ceriatone build I've been fooling around with, but I haven't installed it yet. No idea how it compares to the Metro loop, but it looks decent enough quality. I think I paid $35 + shipping from Malaysia.
Maybe somebody else on the forum has experience with the Ceriatone buffered loop and can post an opinion on the sound quality vs the insert loop.