several years I would think.. Brachys could take 4 or 5 years from that size. my B.albo has grown pretty quickly but not compared to my other Ts. for the G.aureostriata I think they grow quicker than G.rosea but it is still gonna be a good while.
Of the three G.aureostriata is the slowest grower in my experience. My B Vagans and B.albopilosum are all fairly med to fast growers. But my G aureostriata is a dinasoar. I cant get her to grow at all. She has molted once in 6 months and that molt put her at just over 1/2".
Another question. I'm feeding them small crickets,about 1/2 the size they are (except the G.aureostriata because he is bigger). Should I feed them once a week or twice? I don't want to make them grow too fast if they are supposed to grow slow.
Once a week is just fine. You wont have to feed them to many times before they molt up to the next level. Slings grow somewhat fast anyway. Its when they get to the juvi stage where some species start to slow down.