Thanks heaps for the tips Damian. I really appreciate it. $90 sounds like a great price
I'll give them a call tomorrow.
I have read quite a few things regarding msking sure the distance to sensor is important so it's good to hear you confirm that too
I had considered using the visual back too. My mak is an odd thread at the back but I think I've found an adaptor to adapt it to the standard SCT thread to use the wide range of 2" adaptors and diagonals so I might ask them about that at the same time
Thanks again