Good news/Bad news.
I've got good news and bad news.
The bad news is that the micro-disk is (reported to be) no longer in production. The dies got damaged somehow and replacing them is more money than the consumer demand justifies.
The good news is that it is not that hard to make one of your own.
The depth of my Auto-disk is .452" A piece of plastic that thick and 2.3" wide will slip into an auto-disk in place of the disk. Once you drill a hole in it just the right size and cut a notch to accommodate the actuating arm you will be able to make your own auto-disk insert of any size you want. If you make two half-height inserts, leaving one stationary and the other sliding back and forth you have just made a micro-disk.
It is something I have been working on in my spare time.