Stick with home divisional underdogs. Winner almost every year. You can filter it down further, but just blanket betting is going to end up making you plus almost every single year.
Using your +140 theory it is a loser. The only time it makes money is what I mentioned above:
363-535 (-1.43, 40.4%) 4005 (on home dog) -9150 (against)
1252-2146 (-1.01, 36.8%) -7290 (on away dog) -14660 (against)
Also, on totals, read:
The Physics of Baseball by Robert Adair.
Some important points on weather>
Wind makes the biggest difference. The average wind speed in the United States is about 10 mph. Assuming all other conditions are normal and the ball is hit at a 35-degree angle, a 10-mph wind behind the ball would push a 400-foot homer to 430 feet. With a 10-mph wind working against it, the 400-foot shot hits the center fielder's glove at 370 feet.
A decrease in barometric pressure also makes the air less dense. For example a home run would go about 20 feet farther on a 95-degree day with a barometric pressure of 29.50 inches of mercury than it would on a 45-degree day with a pressure of 30.50 inches.
A fastball thrown at 90 mph into a 10 mph wind would have a ground speed of about 89.3 mph; if it's thrown downwind, it would be about 90.7 mph. A 10 mph crosswind will blow a fastball off its path by about three inches.
A crosswind has an even greater effect on slower pitches: curveballs and knuckleballs.
A baseball that would travel about 400 feet (120 metres) on a day with calm winds would travel about 445 feet (135 metres) with a 15-mph (25 km/h) wind behind it.
