The Williams FP-AG-TK sight is an air gun sight with target knobs but based on several reviews it can also be clamped on top of the 10-22 Weaver TO-9 scope base. Anyone using one of these or the Williams FP-RU-TK model that's designed specifically for the 10-22 and requires d&t to the side of the receiver? It seems like a taller front sight would be required for either one and I'm guessing a lot taller one for the air gun model that might not work so well for close range shots.
I have a very old Foolproof FP-RU sight on an equally old 10/22 carbine. it sits very low to the receiver and yes, it still requires a taller front sight. I can measure it tonight if you want. Adding a scope base under a peep sight would require a very, very tall front sight, off the top of my head I'm guessing maybe 1" tall?
That SWAG is based on having recently tried a Skinner 860 Reliable on another 10/22 since the aperture center only sits some .4" above the receiver, and that was still way too high. From my calculations it needs about a .73" or so front sight and Williams doesn't make one that tall. Skinner does make a .75" tall blade front sight but only for a 1/2" base. In an email exchange with Andy he said he could custom make one with the proper 3/8" base. I forget the price but it's either no extra charge or at most a small fee.
FWIW I put a WGRS Firesight kit on that second 10/22 and the Firesight front sight replacement Williams includes with it is the correct height. Trouble with that is that Williams has really cheapened their WGRS to the point of almost not being usable. The little set screws are tiny and of soft steel and easily buggered up if you try to put much torque on them. Eventually the jarring of the semi-auto action can loosen them unless you put a dab of loc-tite on them or as I do, drop a dab of clear fingernail polish on them. I had a WGRS from another project 25 years ago which has a much superior set screw arrangement so I took the slide off of that to use on the WGRS 10/22 base and that works just fine.