I agree with the math that plain martin will always lose, but by modifying it, a larger variance can be caused, giving you a slight edge. Its not perfect, and i'm always looking for new ways to improve the bot and increase the variance, if you have any suggestions, i'm open to them
You can easily max your variance without any bot: take all the money you intend to bet, and bet them just once.
That's the minimum variance possible.
(the odds are still on the house, of course)