Tim, if you like'm you're going to use them a lot. I'm a dentist and I have a first rate set much like you pictured in3X with a 14" distance to target. It cost me over $1000. For most dental work I just use reading glasses, with the 3X magnification for really fine work.
For gun work, I just use ,and like , a cheap headband thing from Brownell's. It's probably 2X.