There is only an access panel on one side. It's not necessary to have one on each. I didn't have any problems installing the driver with access from only one side. I used hex bolts.
As for the number of panels per sessions, The only time I had to stop due to glue drying was on the lip for the access panel to make sure the glue set flat and smooth.
Basically, I put the glue down, set the piece, clamped it in place, then used a ton of nails to hold it in place. Once the nails were in, the clamps came off.
It's tricky clamping pieces in place with the glue making them slide around and creating a mess, but that's basically the fastest way to go. It was tougher since I used 30" panels. You'll need a lot of clamps =]
Looking at your pictures, it looks as if you didn't use any fasteners on the second side at all. Is that right?
Also, how was getting the driver installed with only one access hole? Not too bad?
How mant panels do you guys installin one session? Only one until it sets? or more as long as the clamps of the previous work don't get in the way?