Yes, a C14 will fit into a 2.3 Sirius dome. Doug George (MaximDL developer) had a similar configuration on a Paramount ME a long time ago. Doug's old set up can be seen here -
http://cyanogen.com/doug/construction.html
You would be surprised what you can fit. I had my 12.5" RCOS in mine for a while which I found a little scary. Peter Ward has fitted a 14.5" RCOS in his 2.3 Sirius dome before. Neither of these are small scopes.
If you are automating the shutters, just make sure the scope is parked and/or dome rotated into a safe position before shutter is closed. The lower shutter actuator enters the dome a fair way when closed. You could easily smash it through your corrector plate if not careful. When the shutter is open, its not a problem. Of course, if you are not automating the shutters, no need to worry about it as there is no actuator for manual operation.