Ah well good luck to you then. There is a big flaw in your plan though - and that is you'll have an awful lot of guess work involved in getting the correct values to feed into your calculation.
First of all you'll need to know the range to the target, secondly you'll need to know the angle of elevation from the horizontal (not necessarily level with the ground). It's a bit easier to do that in FT because we can rangefind with our scopes and we're allowed to fit inclinometers to our scopes. In HFT you're going to introduce far more errors in your expected POI by getting either of those values wrong than you are by the difference in POI for an inclined shot. You're also going to have to cope with cant and parallax error that you can induce by taking an inclined shot. All of those factors are going to mean that with a wobble factor of less than half the width of a pellet, you'd better hope that luck is on your side because you're certainly going to need it.
Anyhoo, that's for you to figure out. Hopefully I've done what I set out to do - I've explained why the Rifleman's rule is wrong and I've explained the reason for the change in POI that happens for inclined shots - the rest is down to you to figure out.
Last edited by Brian.Samson; 30th January 2016 at 06:28 AM.