I'd like to buy a good general purpose loupe for examining pens and doing a bit of nib smoothing and adjustment. Reading through prior posts it appears that one can either: 1) buy something for $5-10 on eBay, which is considered either junk or wonderful depending on the commenter or 2) opt for Belomo, which all who have agree is very well made and has little distortion--I have already decided that I would prefer to buy better quality than buy twice I have ild/mod myopia, astygmatism and now (joy!) presbyopia so responses from the over 40-50 age group are especially valued. If you have used Belomo loupes, what is the best magnification if I only have one loupe? I'm leaning towards 10x-12x, but would appreciate input since I cannot test them myself. Thoughts appreciated.