I suggest the normal trackball instead of the Highball variety. My Highball tends to jump and skip on its bearings, and is easily lifted off of them if your hand hits the edges instead of the top center. The only part of the ball surface I can use without this happening is the portion that is exposed in the normal trackball.
Also, keep your control panel horizontal. I think some left-spin-tendency I'm experiencing with my ball is because of the angle of my panel.
BTW, I played with an old Centipede machine a few days ago, and the ball seemed really tiny. I like the bigger ones more.
Oh, and if you're interested in a transparent glowing trackball, the Happ part number for the light holster piece that holds the lamp underneath their trackball is 91-1224-00. You can also order the trackball with it already included, you just have to look closely at their trackball mounting diagrams and enter a part number manually.