Edge is what you make of it. If you believe you have a 4.8% edge, then by all means bet to win 4.8% of your bankroll. However the answer you are probably trying to figure out how LGH's edge differs from yours and how does he get the number that he does. I'm sure he (like myself) uses
this tool or something similar to determine edge. -114.5/+114.5 puts out a 2.56% edge, but -119/+110 (what Pinnacle's number closed at) punches out 2.75% on +120. The calculator works a little different for baseball seeing how the only option is totals, so just punch in Pinnacle's number atop
any other league (for the most part, line doesn't matter just don't go above and beyond) your books numbers in the fave price / dog price white boxes and you should be able to find out the edge you have on Pinnacle's current no vig line.
After accumulating 2000% worth of edges your bankroll should double if you follow Kelly Criterion (the edge percentage) exactly. Also, don't limit yourself to baseball when the same theories can be applied to other sports. I don't know ANYTHING about tennis, but I do know that Pinnacle (to quote the sharpest sports bettor I've ever read) "is an efficient market and/or possesses a crystal ball" for bettors to follow. Alas, I am starting to win at another sport which conveniently happens to go on when there's nothing else to bet on and your bankroll is just sitting there screaming "make me larger".