Guidelines for sterilite tub sizes?

I'm about to build a snake rack, and all of my current 'biggins' seem to comfortably fit in 28 quarts. I'm unsure of what to put my 300g in, and I was wondering if there was rule of thumb or guidelines that I have missed in regards to appropriate tub size for your snakes. I also know that sizes can vary with bps though. I have one female who is very long, but not very thick(very finicky eater) but then I have another female who is short but massively thick(usually eats whatever the previous female doesn't).

I use 3 tub sizes, 6qt, 12qt, and 41qt.

Hatchlings to 300 grams stay in the 6qts, subadults and adult males stay in the 12qts, and breeder females stay in the 41qts. I have a couple breeder males that will need to be moved to a 41qt in the next year or two, but they fit in the 12qt fairly comfortably for now. If they look cramped I move them up a size, if they are poor feeders I keep them a smaller tub. For example, I have a couple 400 gram animals in the 6qts because they don't eat well. I also have a couple 1,000 gram females in 12qts for the same reason.

This is is good thing to follow ^^
I've heard different tub sizes (6qt, 28qt, and 41qt.) which is what I will probably follow when I start breeding.

I use 4 sizes. 6qt for hatchling racks. I have a few racks that fit 2 12qt or 1 28qt per shelf for flexibility of moving smaller babies up without having to build a new rack. Then I have my adult rack for female breeders only with 41qt.

6qt - hatchlings to 200g
12qt - 200g to 600g
32qt - 600g to 2000g (or adult males)
41qt - 2000g + females

I've only had 1 male ever in a 41qt and he was over 3000g. Biggest male I ever had. Also if I move them up I make sure there is more in their tubs. For example an 1800g female in a 41qt tub will have 2 hides and a large water bowl. If I have a 3500g female in a 41qt tub, I just give her a water bowl with no hides.

^edit "2000g" female in 41qt tub. I don't move them up smaller than that. I also don't breed them smaller than that usually.

Currently I'm using 6qt for my hatchlings under 300g, a 15qt for 300g to... I'm not sure yet, because I only have a hatchling and two girls just over 300g. :P My big female is in a 41qt. After the two girls out grow their 15s, I think I'll be getting them 32qt after they hit 600 0r 700g.

In certain instances, you can eyeball it. One of those 300g females is actually fairly thin (not underfed, just growing longer first rather than thicker) and I was honestly surprised at her weight. I wouldn't be uncomfortable putting her in a 6qt, but I had a 15qt already prepped so that's where she went.

My plan was to provide hides and water bowls until the 41qt size (my "rack" has open sides) and then just water bowls, but my 2500g or so female started to act particularly restless, so I gave her her hides back.

- - - Updated - - -

Currently I'm using 6qt for my hatchlings under 300g, a 15qt for 300g to... I'm not sure yet, because I only have a hatchling and two girls just over 300g. :P My big female is in a 41qt. After the two girls out grow their 15s, I think I'll be getting them 32qt after they hit 600 0r 700g.

In certain instances, you can eyeball it. One of those 300g females is actually fairly thin (not underfed, just growing longer first rather than thicker) and I was honestly surprised at her weight. I wouldn't be uncomfortable putting her in a 6qt, but I had a 15qt already prepped so that's where she went.

My plan was to provide hides and water bowls until the 41qt size (my "rack" has open sides) and then just water bowls, but my 2500g or so female started to act particularly restless, so I gave her her hides back.

I use 6 Quarts & V18 for hatchlings - 6 quarts are for available hatchlings the V18 are for the ones that do not sell quickly or my holdbacks.

After that they go in their adult tubs 32 quarts for males and V70 or 41 quarts for females.

6qt to 300, 15qt to 600, 28 to 1300, 41 qt higher than that

This is just a rough outline of how I personally do it.