One thing a lot of people forget when starting out with an SCT is that it is very useful to have a cheap low focal length eyepiece (or barlow combination) for collimation. That may be empty magnification most of the time, but when you really need to collimate, it can be much easier collimating at 3mm vs at 8.
Build a simple artificial star and you can collimate even when the seeing is bad. Mine cost me about $10 in irrigation parts at Bunnings. I'll post some pictures of it one of these days
