I'm 51 . 20/40 x 18/20 corrected to 20/20 .
My old 6-9×40 will do the job 6x and up most days but the light has to be facing the target . 10x would be plenty on the corrected down side but the corrected up side looses about 4× with glasses but only 2 or so with the contact .
The 3-9×40 Tasco 94-96' is way ahead of all but the Weaver V9 196?-72 .
I don't have any really good late model glass .