Dripht,
I tried the template that kirk posted but after building it and going to the arcade I realized with that template the spacing was to far. I am not quite sure what the spacing is on that template but it didn't seem like the real SF in the arcade to me. Hey maybe I did something wrong when I printed it....anyways I am now using 1 1/2" spacing.
I also think it might have to do with the button you use.
The best suggestion I heard was to lay out your control panel on a shoe box or some other type of cardboard box, and then you can try out diffrent layouts buttons in a curved layout, straight curved , also how many buttons 6 or 7 buttons...etc
Just my 2 cents
ED