Years ago I bought a Varga frame, they are all adjustable and I personally don't think sapending 2 or 3 times more is really worth it. It's all down to the lense and that is down to your optician. I visited an optician who works at Bisley and is based in Bristol (at the time I lived in Swindon) he tested me and supplied a suitable lense, the prescription is more like reading glasses rather than distance glasses as you need to get your front sight in sharp focus as you are probably well aware.
https://jhs-eyewear.com/pages/jh-steward-bisley