The only problem I see with your strategy is that when you switch to tight aggressive what if you dont pick up alot of hands. Some people might start to catch on to this and there goes your image. Plus the blinds will start to be getting higher and you might be playing the short stack. But if that works for you keep on doing it.
What I would do in the sitngo is get in cheap while the blinds are low and try to catch a big hand to double up. And then I when I get chips I can start to bully the table when the blinds get high enough and just go from there.
"I can read you faster than I read books"