Didn't Kensington also make a hybrid USB and ADB trackball with a similar adapter? I wonder if the adapter and circuitry are the same between the two products.
I think their idea was if you wanted to start the computer from a CD not in the computer from a cold start, you'd hold option to get into the selector, from there, you can eject the optical drive to insert your disc, hit the rescan button and you're set.
Don't forget with the Studio Display you can power the computer on by touching the power button on the display. Puts it to sleep too. Bonus with ADC is you get USB through it so you've got extra USB ports to play with on the back.
That original 30k qualifying score was quite the reality check for me. I'm realizing after a little of practice time my reflexes aren't nearly as good as they were 30(!) years ago.
You probably know this already if you've hung around the vintage Mac forums for any period of time. Remove the PRAM battery! As far as I know (someone can correct me if I'm wrong) you don't need a battery in that machine for it to start up and run properly. You'll just need to reset a few...
I am very glad this thread got bumped. I've been meaning to post asking about the sweet spot OS as far as speed and features for a processor generation. Such as, don't run OS 9 on anything lower than a 603, OS 8 on anything less than a PPC 601 otherwise you're looking at poor performance.