I think front to back you will be fine. Once you reach 3/4" things get tighter. Rim width to tire width, mph, tire construction, etc.

I know cost is high, but the time to switch to a 10" wide rim with the appropriate back spacing is when changing tires. After you run the new rims/tires and have no problems, you can sell the old rims to offset some of the cost. I see those tires are really 10" wide tread.