I use this one my HW35e.It was also used on my R1.HW did make rear peeps for there HW55 series target rifles but the grooves on those rifles were more than 11mm.Pyramyd Air sells this sight too:
Thanks for the comments. I've been doing research on this and determined the most practical solution is to live with the 5 inserts on the OEM HW front sight. The most economical rear sight looks to be the Williams FP AG TK and get a Gehmann PH510 iris. Is the comb height low enough on the HW35E to use this setup?
I also like older Anschutz rear diopter match sights. They fit any 11 rail and work great on HW rifles.Note that the Gehmann irises typically fit any German sight (9.5 x 1.0 mm eyepiece mounting thread), but for a Williams sight (7/32" x 40 thread) you will need to either get the special Gehmann model made for this, or a separate adapter. The latter is the more versatile option - lets you move the iris to about any airgun sight you are ever likely to own.Pic is an old Anschutz 6702 on an HW 55 with 11mm rails.
I’ve used the Williams and they work but, at least for me, are a little fragile feeling. I’ve stripped screws with them. I have several Air Force Adaptive rear sights on Weihrauch rifles and have been very happy with them. I have 1 Gehman compact on an HW35e that has done me well also. All are/were used with the stock front sight/apertures. Here are some pictures of the sights on the guns. I don’t have any of the Williams handy.
Sorry I see several of the rifles are HWs-early and not enough coffee yet-but the question is still how to install a better front sight on an HW with 9mm dovetail when it appears the modern front sights, German Anschutz, Gehmann, Centra, are 11mm?