My Weaver T36 is fixed 36 magnification, the 40mm objective with a 1" tube means its quite a dark scope, it's really a benchrest scope but it works ok.
Before that I used to use an old boosted Leupold FT scope on 50 mag, it's a nice scope, the higher mag was great but the reticle was a bit "busy" and it was heavier.
The lowest magnification i would use is 20, i have a Leupold 6.5-20 EFR on my old ProTarget, its nice but higher mag would be better.
Rather than closing my non dominant eye i use a blinder, i find i relax more shooting with both eyes open and it seems to help stability.
Higher magnification and standing shots can be difficult to begin with but it really forces you to work on your breathing and your stability.
If you can get comfortable with it you are shooting from a more stable platform but it's something to try between leagues.