Thanks for the replies people, I'll try that Best Practice software and see what I can get out of that, slowing down stuff- especially slap would be useful even with the tabs.
So this trust your instinct thing, the hard part is that I don't really have an instinct.. every now and then I'll be playing a tab and it'll sound a bit wrong and I *might* be able to correct it, but I just don't feel like I know what I'm doing. Even tuning can sometimes be frustrating and I'll have to go back to a tuner.
For scales- where should I start? Is there a set list of scales that I should learn as a beginner and work my way through? I know how to play a major and minor scale across three strings (I think).