I have a family member that I have been taking bets with for years and I've made literally thousands. We don't charge vig, but I constantly move the lines in my favor and he rarely fails to bite. We're talking the typical "chalk and the over" fish. So my question is, in the NFL, say Team A is listed at -7, and I move it to -9. How much are those points "worth" by percentage? My estimation is one point should be worth about 2% in my favor taking a 50/50 bet and moving it to 51/49, 2 points 4% 52/48, etc. Any links on this and/or help is appreciated.