ATM Experiential versus Emperical cage height minimum

[Tom Lakovic <tlakovic@comcast.net>]

Hi, I need help in determining my minimal 'pretty good' cage height and
still have adequate baffling without the need for a velcro on extension. Is
there such a thing as a 'rule of thumb' minumum that does not require stick
on extensions in the field? I've seen the empirical (true) answer to that
question and it's like 2x or 3x my physical minumum of 8" needed to support
my vanes and focusser but was wondering how much more I would absolutely
need to add to that 8" height to be well, 'good enough' from your
experience...good enough to leave the floppy extension at home if you know
what I mean? If say 12" is really not enough (IS IT?), then maybe I'll just
have to accept it and instead build the cage at it's physical minimum of 8"
since I'll have to tack on kydex anyway.

Thanks, Tom.

Details: 2 ring design 15" ID, primary=13.1", stalk, stalk, vanes and
secondary height 7",  2" focusser at the bottom ring.