Rob, you're getting near. The sphere is the main part of your prescription, the magnification if you like. Base your shooting estimation on the "near" or "near/reading addition" of the prescription and make your estimation from that.
My right eye sphere is +0.25 and the near addition is +2.25 (near sphere = +2.5). I ordered lenses to +1.0 and +1.25. with the astig cylinder as prescription. At the moment, the +1.0 is correct.
My last pair of lenses from 2 years back were +0.5 and +0.75. As my eyes degraded I went from the former to the latter.
Whatever your own figures, your shooting lenses will be less strong than your reading lenses and stronger than your distance.
Sorry if I can't put it into better words!
Walther CP-2 Match, FAS 604 & Tau 7 target pistols, Smith & Wesson 6" & 4" co2 pistol, Crosman 1377,
Baikal IZH 53 pistol, Gamo CFX Royal,177, Umarex SA-10 CO2 pistol.