What's your idea of growing it up "slowly"? Do you mean to feed it "just enough" so it doesn't spurt on you or so it doesn't grow to its full potential?
IMO if it's a baby/juvie you need to feed it at least once a week, but I have my '12 female (mainland ST) on a five say schedule. Snakes grow at different rates, and feeding less or small feeders isn't fair to the snake or responsible. Even though my girl is on a 5 day schedule she's still growing at a slower rate than other mainlands I've seen just because that's how she is as an individual. My idea of "growing up her up slowly" would be a 5-7 day schedule until she gets onto larger feeders.
Anyone who's looking into getting a retic (dwarf or mainland) needs to prepare for a monster since most get to a very respectable size (males included, and some grow faster than others). IMO wanting a mainland tic but not wanting it to get to a massive (yet healthy) size doesn't make much sense in my mind.
Edit: Saw your #11 post OP: I would still feed at least once a week if it's a baby/juvy. I personally wouldn't feed any less frequent than that, hence why I have mine on a 5 day.