I use MaximDL and use parameters mostly calculated using the resource on CCDWARE plus a bit of trial and error depending on seeing.
http://www.ccdware.com/resources/autoguidercalcv4.cfm
With the short focal length refractor, as I have a self guiding CCD for LRGB but behind the filters I take advantage of that so no guide scope or OAG but its not so good for NB. I can get away with guide exposures every 8 seconds at this focal length, usually binned, prefarring to avoid moving the mount too often if I can help it.
For the GSO RC8 I use an MMOAG which is excellent. Guide Star shapes are crud due to the combination of curvature you get with those scopes alongside the size of the chip (stl6303) but you can work around that and I get good results. Depending on what stars I can pick up for guiding I set the exposure length for around 6 seconds.
Good thread, Greg.