I agree with Ron, regardless of which peep you choose, you want it as far back on the rifle as possible. My Omega X7 came with the WRGS installed right over the breech. Kind of wish I had the FP for the reasons you stated - easier to adjust and more elevation/windage range.

You can call the guys at Willaims for some advice. I did when I was looking for a peep for a somewhat obscure rifle and the guy I talked to was very knowledgeable and helpful.