Have you tried the Mike Weasner's Mighty ETX site? I haven't bothered with the 90 but there is lots of info on my ETX 125PE.
John
-------------------- My wife shares my love of the night skies and tolerates all of my other hobbies.
Televue Pronto w/Starbeam pointer and Televue tripod
Meade 2045D, ETX-125PE, 12" Lightbridge
Celestron: 7Amp PowerTank, 15X70mm binoculars
Meade, Swan and Televue Lenses (33, 26, 20, 15 & 9mm), Televue Barlow
Catsperch Observing Chair