Nothing but physics...and Newtons laws...for every action there is an equal and opposite reaction...F=MA...or the easy way...use a recoil calculating program found anywhere on the net. Check out some of the muzzle brake forums and makers and look for Recoil.exe...it will calculate recoil with or without a brake.
Tikkanut...you could use a brake, as many who understand the nuances of Newton do, to keep the muzzle down on your Vartag so you can see bullet hits...one of those old timey tricks used by 22-250, 220 Swift, 22-284 shooters in the old days before everyone got to be smarter than the average Hogan. If you need an Xtra HD recoil pad because you got your stock too short, I don't see any reason not to go for it. Hey, my last 22 lb benchrester 22-284 had one...sometimes I think my 17 FB could use one also. Of course recoils is totally subjective so if the Vartag is too much for you at the other end...well I wish I could help you, but I just can't reach you.
What is it someone said..."No good deed goes unpunished".
'Njoy