Hi Glen,
Echoing others, OAG is the way to go regardless of FL, unless you have limited back focus.
Even better, an integrated OAG such as in QSI cameras or in SX filter wheel.
OAG comes in handy with longer exposures in particular, such as in narrowband imaging.
On a personal note; having used both an OAG and a guide scope (actually, a couple of each), and being eternally enriched by pros and cons of both systems, I am not going back to guiding with a guide scope
