does the focuser have a 2″ drawtube or is it only supporting 1.25″ extras??
you may struggle with vignetting as its quite a small aperture on the eye piece as its quite narrow
the other thing is that the length of that tube could well give you issues with focusing as the backfocus on that newtonian may be limited
can you bring it down to CAS one night n we can have a look
cheers
Simon