Either/Or Shawn, the chip type doesn't matter. I use at various times a ToUcam 840 or 900, a SAC 4.2, a DSI original colour (which works great with K3CCDTools BTW), a DMK and once my ATiK. I didn't like the LPI cos I could only get it to work with the Meade software which I found to be a pita.
Through my ED80 with the Canon 300D attached I have guided through a Stellarvue finderscope with np at all. It would most likely be too short for an SCT unless the SCT was using a 3.3 Focal Reducer, but I have heard of someone guiding an 8" SCT using a 200mm camera lense attached to their guidecamera.
Save yourself some heartache though and get a decent refractor that can double up as a widefield imaging unit.
What are you trying to image through? You might want to think about an Off Axis Guider ( I wouldn't, but some swear by them. I just swear at them
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