Good luck!
Have you thought about playing the -1 RL instead of the -1.5 RL? About 30% of all games over a MLB season will end with a one-run difference. Therefore, instead of losing on those plays, you would push and save yourself a lot of profits using the -1 RL for this system.
If your book does not offer a -1 RL (neither of my locals offer these), you can do it yourself by betting half of the wager on the ML and the other half on the -1.5 RL. For example, assuming your 1x = $100 and Boston is a -150 ML favorite with the -1.5 RL at +125, you could take Boston ML (-150) for $50 and take the -1.5 RL (+125) for $50. If Boston loses, you lose $125. If Boston wins by 2, you win $112.50 and if Boston wins by 1, you effectively push because you win on the $50 ML wager but lose on the -1.5 RL wager. You are basically trading away part of your potential profit of playing the -1.5 RL for the ability to push on the one run games.
With this particular system you are trying out, I think you would win more using the -1RL (despite the smaller payouts) because you would push on the one run win instead of losing. I actually think there is a math formula you can use to confirm whether you are better off with the -1 RL v. the -1.5 RL, which is based on historical results of the teams (i.e the number of games ending at a one run difference) and the average odds those teams generally face on the ML and -1.5 RL. Good luck!