Looking for first rack system

[StillBP]

I know every snake is different, but if you had to take a guess(based on experience), how common is it for a female BP to get over 2000g? My GF has a 7 year old male that is a little over 900g, and I have an almost 8 month old male that's a little under 300g. I have zero experience with females, but I was thinking if you arent breeding them it would be kinda rare to have one get over 2000g. But that was just a guess based on my zero experience.

I was thinking I could get the 5 tier sub adult rack, but I guess I should play it safe and go with the 3 tier adult rack.

most of my females are 2200-2800g but my big girls are well over 3000g. Granted I breed but I'm pushing 50 females and only two are under 2000g and one is 1800 and has always been small the other is a problem feeder. when it comes to girls I go big on their tubs