My wife was playing 720o for the 1st time on my finished cab tonight, and it took about a minute for her hands to start cramping up. The panel with the spinner on it just happens to have Happ illuminated PBs for all the buttons, you know for Missile Command etc. I noticed the spring tension on these seems really firm, and I do usually have to call it quits after a game of MC for the same reason.
So I took a look under the hood, to see if the springs were anything I could replace. I thought I'd try a button without the spring, and it worked pretty well! So well that I pulled all rest of the springs immediately. This actually makes the buttons much more responsive, having a shorter throw more like the old Missile Command buttons that you barely had to push.
If you like the feel of leaf buttons but are forced to use microswitch buttons, you might want to try this. The spring of the microswitch is more than enough to return the button, and you get a much faster response when firing.
Just thought I'd let you all know..