You're not helping your case, assuming they're coming from a position which is not utterly sold on the idea of independence.
If they aren't sold on the idea of independence because they think the SNP giving 16/17 year olds was partisan then they are stupid, I'm sorry. The 16 and 17 year olds thing was completely overblown by the media to the point that it actually became a serious topic of discussion with respect to the vote - as if our future has anything to do with voting rights being given to younger people who, according to opinion polls, aren't 100% on independence themselves either. If the opinion polls are to be believed, a large majority oppose it. Based on my own experiences I think they're just like every other Scottish demographic - a third in favour, third against, third undecided, some weight in the "against" camp.
I have all the time in the world to try to convince people who have grown apathetic and think all parties are shit, or want to vote Yes but are worried about the economics, but people like those you've described are just looking for faults in the SNP. I don't have time for people who are so small minded; those who have reduced the entire issue of independence to stuff like whether or not you like Alex Salmond/SNP. Not at the moment anyway, maybe in the next year or so after we've dealt with the more sympathetic "undecideds" we can consider trying to convince people like that.
I'm talking about whether there would be hesitation if Scotland was better off but Britain as a whole was that much worse off.
I don't think there would be much hesitation at all. Labour have brought up some vacuous stuff about how we'd be "dooming England to Tory rule" (as if denying the English of electing their own government democratically is a morally-sound argument), but people just don't really care about it. We're much, much more focussed on Scotland at the moment and how we will fare.