Found the below two items.
The bolts are from Home Depot (or many different places)...Hillman brand, 2 per pack...1/4-20 x 1" Socket Head Cap Screws. I only went with one inch on these because there's only a 3/4" baffle thickness where the driver flange is seated. You can get them in stainless or black oxide finish.
You could, of course, find coarse thread "screw-point" variants of these if you are going to screw down the driver and not ever or often see the need to remove it for any reason.
I liked the idea of being to unbolt as often as I wished anytime and not worry about holes becoming bigger flaky holes in MDF...so I am using a 3/8" pilot hole and inserting the below 1/4-20 knife thread brass inserts. You can find these for about 50 cents each at many different places including McFeely's online. You can insert these from the back or front of the work piece.