I agree with Jeremy. I had considered exactly the same proposed setup as yourself, but concluded i wouldn’t fit in the dome with the scope 😉 However i suggest that a motorised dome rotation would overcome the narrow slit difficultly. It works very well on my 2.7m Pulsar. I align the aperture on the OTA, and select sidereal rate on the control box. The azimuth drive system can be retro fitted.