Just a hind sight kinda opinion here. get the most sensitive guide camera you can afford!!!
qhy5 and SSAG is fine for most things but if your really interested in doing well the Lodestar from Starlight xpress is one of the smallest/lightest and the best but it is also 700 odd dollars. Sbigs 402ME but thats even more expensive but stupidly sensitive
it picks up the HH nebula in a 2 second shot
Stay clear of modified web cams they really are not sensitive enough to give you good stars although they work ish.
Brendan