I would start with the $7 (or so) SNGs in order to get a feeling for the game. That is what I did when I switched from Turbo to Hyper-Turbos. In the first 100 to 200 games it is IMO all about adjusting your game and therefore I would chose a middle thing between "not to expensive to make mistakes" and "the opponents can play - kinda". The second one is IMO not true for the $1.50 SNGs. Takeing on a fish on the 15 to 60$ is the same procedure and the skill jump from $7 to $15 or $30 is much smaller than from the $1.50 to the $7.The rake should rarely be the problem (well, unless you play on PartyPoker where they take up to 10% or the likes...)Also keep in mind that you should use a 75 to 100 BI BRM

A ROI between 3 to 7 % (alltough 6-7% are really top) should be possible.1 to 2k games should be enough for a sample size. The ROI is small and so the swings can be huge.If you wanna move faster, you could sign up for special coaching, do extensive session after analysis etc. pp. This all should give you good input if you are beating the stakes or not.Battleing fish is most of the time pretty much the same. But it makes a difference if you battle a reg on $7 or on the $60 HT.