Well, mine is still going strong. I've got another one, NIB, but it got some damage in shipping. When this one goes in, out comes that one.
I measured 9 5/8" from the forward full bulkhead to the hub. I got 5 5/8" from the firewall on the engine box to the hub. The cowl ends a little bit aft of the full bulkhead, and screws through the cowl into that bulkhead, to secure the cowl to the nose.

I'm using an FPE 2.4 (42 cc) gas engine in mine, swinging an APC 20x10W. It goes like hell ... I wish I were a better pilot to get more out of it.

Good luck with it.