Hi Marc
I haven't researched what/any difference between N and ED, but for mine with a QHY9:
F5: 2" Tak ocular adaptor : 2" barlow GSO (lens removed) : 2" nosepiece on M54 thread on the QHY filterwheel : FW : M42 adaptor/window on the 9
F3.7: Reducer: M54 Tak adapter : Precision parts M54 male to M54 male (13mm) to FW : etc
Haven't devoted time to figuring out the extender as yet. After getting a precision parts fitting made so the 3.7 lightpath is all screwed together, I find I'm actually more comfortable with the dodgey F5 hodge-podge usually. I wouldn't like to be doing this with a bigger chip though.
Tak adaptor diagrams sure are scary, and nothing is cheap. If any of above is of interest I don't mind taking a pic for you sometime.
Have you seen this page? Mainly for ED, but pics and diagram links useful.
http://www.nigelaball.com/ResourcePa...kadapters.html