We put ag tires on our golf cart, with most of the weight on the rear axle, (motor, people), it goes through anything until it gets hung up. It does get hung up rather easy though in deep mud or snow. haha.
Ours is a 2 stroke, and from what golf cart guys told us, they run a low amount of 2 stroke oil because the engine doesn't get that hot as a golf cart, and it would smoke too much and foul the muffler. Mufflers for these are stupid expensive.
If you are going to run the golf cart long and hard and it gets hot, more oil is ideal. Thats what I hear anyways, not even sure if yours is 2 or 4 stroke or what, but just saying.