Well TBH there are too many variables to consider for there to be a "best" setting option. The best you can do for now is run the debugger with arguments to increase jpeg compression/bandwith allocation to get the best connection. The Wiki also suggests using channel 1,6, or 11 on your router to further diminish interference on a 2.4 band anyway. Other than that, you're already getting the most you can out of THAT particular game (Maybe a bit smoother with L2 enabled?) it runs average of 35 FPS anyway. Some games don't run at all, others are choppy etc. It all depends on the hardware requirements of the game itself. IMO anything 3D giving you 30+FPS with minimal frame drop is pretty amazing.
EDIT: Distance is always a factor within wireless networks. If it's that close why not use a LAN?