Phoned Peter Read of SDM today, whilst he couldn't supply me with a holder he generously gave me some good advice. What I thought was a problem with the Astrosystem spider arrangement turns out to be a better more solid mounting than the original.
The Astrosystem's much taller assembly requires it to be mounted right on the tube end ring approximately 40mm further up the tube. So instead of mounting onto the thin tube I can mount them onto the 9mm thick end ring. Sounds good to me anyway.
I have ordered the Astrosystem heavy Duty Holder with the DG-1 heater and an Antares 2.14" 1/30pv mirror. Should be a nice match with my new primary.
So thanks to all, again.
