a comment on cool down ... i do not have any modifications to my LX200, but i don't cool it as daniel describes. i leave the focuser in place and turn the tube to point straight up. heat rises, the corrector has maximum view of the sky, and cool down proceeds fairly rapidly in my experience. my issues with daniel's method (also recommended to me by the manufacturer) are: (1) the open back allows dust, debris to blow into the OTA, where it remains until the thing is taken apart; (2) heat rises, so heat migrates across the mirror from bottom to top, producing a thermal gradient that can distort the optical figure. (wolfgang rohr makes some mention of this in one of his reports on the mewlon.) i know there is the story that infrared is reflected from the mirror coating and therefore has to go out the back of the mirror, but the reflective coating is also heated by conduction and i believe that largely negates the supposed reflection effect.
in any case, i'd be interested to hear how far the cool down issues with the SCT can be remedied with different cool down methods, and any demonstration that venting through the visual back is really optimal.
Do you like your Royce optics on the 250? How do you compare the planetary views between your two DK's -- Tak and Royce?