Positioning bifocals in nontraditional positions is common practice in Safety glasses. On several occasions I purchased glasses with the bifocal on top. I had painters who did fine over head work.
You might want to have a pair of shooting glasses were the prescription for your shooting is positioned to accommodate your shooting position. Have the far lens positioned so that you drop your head to see distance.
Hunting this might present a problem but for range shooting i think you will like your scores. It will keep you from having to unlearn years of muscle memory.