That's plenty big for those wheels. I have Hoosier 26/9.0-15 on LX wheels and the tires are way too wide IMO. The best combination is the stock SC wheel with the MT 26/10.5-16 ET Street. That tire has 8.0" tread width and fits nicely on the 7.0" stock wheel. Plenty of traction also. Gary ran these on his 11.70 nitrous runs nearly pulling the wheels off the ground.
I've got a set of M/T ET Drags 26x10.5x15 mounted on a set of LX wheels. They could certianly use a wider wheel, but they do get nearly a full contact patch if the pressure is kept down to around 18 psi.