“I just use the standard The Sky X autoguider.” I use Prism… (I used to use PhD2 for guiding). But, in any case, I think main difference is that, if you are using a slit, then the star is double lobed, which can cause problems with normal (unimodal spread function) guiding; hence use of slit guiding. You use a fibre which presents a hole so you can use regular guiding.
” have to take very short exposures….so as not to chase the seeing.” Surely other way round? (longer exposures stabilise against seeing)? I use between 4 and 9 secs…