How many sng at a particular level do you need to play before you can get a feel for how well you are doing at that level? (hope OP doesn't mind me asking that in their thread. I think it's fairly relevant).
Think it was in essence part of their initial op question, but at least it stated clearer with your asking rich.
IMO, 1k stt's will give you a decent idea of your winrate (ROI) for a level and of course more is better, 3-4k would certainly be a pretty clear true ROI I would think as its plenty to ride out swings......sometimes swings on stt's can last for a while as with any variant of poker so the larger the sample the better idea of a true ROI for a specific level.
Regarding moving up I think I would and am more inclined to let my BRM dictate when I move up, unless having some struggles. I had previously worked my way to the 15$ games following a 100bi brm however hit a massive downswing after only being there for a week or so and having to drop back to the 7$ games where the swing continued and this killed my motivation a little. I have just recently started to gear back towards stt's again and currently mix the 1.50 and 3.50 games on a mass multitabling scale (16) to get in some volume, rebuild the br and regain some confidence before I drop the 1.5 games and start to mix the 3.50 and 7$ games. Doing this I can get more volume and in essence can view my games as an avg bi for brm if I wanted to whereby for example instead of playing strickly 7$ games once I have 700$ i can do an even mix of 3.5 and 7$ games when I have 525$ (obv be observent to recognize if getting crushed in the higher cost games).
the quicker the blinds the higher the variance, and therefore the larger sample needed to get a clear vision of your winrate as swings can be harder and for higher volume and therefore the more strict you should be with brm. I use 100bi for the turbo games, I would recommend at least 200+ for hyper turbos and you could do 50-75 possible with regular speeds.....however I would also indicate this all should depend on the # of tables you are running especially before you have an idea of your winrate because more tables is more bi's in play and potential for a hard felt swing if the set doesn't go well.
Think iv gone on enough here lol.