You got it!! Takes just a few minutes to set the speed ring. Sight crosshairs in at 20 [never changes poi regardless of speed ring position] go to 40 or 50 and just turn dial up or down to get what you need, the rest will be right on. If you just use the 30, you may be off a tad at 40 and 50. fiddle w/ it a little and you will be right on from 10 to 50. the 10 is the triangle upside down above crosshairs. A few little tips, once you are on at 20 don't touch the elevation any more unless off at 20, and just turn the speed ring a little bit each adjustment. It's alot easier than it sounds. The closer you get thehorizontal hair in scope parallel to limbs the simpler life will be, lol. You can do the trial and error faster than you can set the chrony up. Well,I can, but I've done this a bunch, think anyone can too.