Ok, did quite a bit of reading, and also went out the garage to get some measurements. From what I've read, a new APE clutch kit does not come with the Friction Disc B (wide tang). I'm not sure if that means it can be eliminated from the stack or if APE intended the buyer to use the original Disc B.
On my previous clutch set up, I had 7 discs and 6 plates with springs measuring at 35.3-35.5mm. No double plate and no Disc B were present, and this brought the stack to the edge of the narrow slots of the basket -nothing sat in the wide slot.
My APE kit comes with two extra plates and two extra discs. When all of this is slid in, the stack, once again, only comes up to the the edge of the narrow slots of the basket (the friction discs are thinner)-nothing sits in the wide slot. The springs measure in at 36.7-37.0mm.
So, do I need to start looking for a Friction Disc B replacement? Is this disc necessary for proper clutch operation? Again, my clutch grabbed fine before the tear-down, but it engaged late when releasing the lever.