Ed,
would you use a spider or a correcting plate to hold the 2ndry? and how would you mount and adjust the diagonal mirror?
If you ever get a chance to come to our Ballarat observatory you can see the 'Federation Telescope'. It is designed for the Handicapped. They sit in one spot and the EP never moves whilst the scope moves all over the sky.
http://observatory.ballarat.net/faci...tml#federation