Using the following calculator will allow you to determine the actual magnification of your lens, based on diopter and distance from lens to eye. Obviously this value changes based on draw length and sight bar extension. Also realize that the "Power" lens that you bought is not really the actual magnification. Unlike a rifle scope or binoculars, where 5X is 5 power magnification. In the archery world a 5X lens is actual somewhere around 2.10 magnification, will vary depending on lens to eye distance, which in turn varies with sight bar extension and draw length. So a 6'2" 32 inch draw shooter will have more magnification than a 5'7" 27" draw shooter, given the same diopter lens. It's companion calculators also allow for you to calculate an estimated area of coverage given a dot size or given an area size which size dot is best for you.
The following is what is considered "Industry Standard" for the archery world.