I TT using the in-game clock 'cos I absolutely hate messing with my 3DS clock unless there's a very good reason.. I only ever TT by day though, and I don't ever bother with turnips.. When I want to get the badges for turnips, I'll simply go to someone else's town to sell them, lol .. 'Cos Joan has always sold them to me whenever I've wanted them
Just my two cents: I TT by using the in-game clock and have never had any issues. I get one pitfall a day like usual, still get special villagers very often, Phineas shows up to give me badges, etc. So I don't see how that's an issue. If I had two games I'd rather use the in-game clock so it doesn't affect my other town. But, like I said, just my experience and opinion on it. c: