Hello and welcome to the forum. A standard battery should do you fine. I know if you get one from "Advanced Auto Parts", it has a one year free replacement.
If your battery is going dead after a few cranks, you need to test your charging system. Very easy test.
If the engine is newly rebuilt, I'd check to see that your magneto plug is in tight. They do make high torque starters but I don't see a reason for you to need that, unless your rebuild took you into "mod"..........
Get a multi meter and test your battery and charging system.......
Welcome to the forum, heres one on me..............:cheers: