Hy was curious why I used such long guide exposures.  It has to do with the way the CEM120 EC2 hi-res dual encoders fight with autoguide pulses.  Here's an example, where I started off with 1 second exposures, then switched to 4 and finally got good results after 6 seconds.  With my mount there is little difference between 8 and 15 second exposures.  It certainly helps when using an OAG as my fields are filled with stars!   But when my polar alignment is off a tad, or it's windy, or very poor seeing, these long exposures are not the best.  In those cases, I would get better results if I could adjust the exposure length SEPARATE from the exposure FREQUENCY.  For example, a 3 second exposure every 10 seconds - vs long 10 second exposures.