Question: Need opinion on 20 long... adding another axie

Hey folks, i know ideally the rule of thumb is 10gallons per every axolotl.
Currently i have a 20 long with three 8inch (growing) axolotls. two females and a male.
I am attending college and our first year we have to live in the dorms and technically can only have a 10 gallon, tho i have my 20 long. i have someone in the area whom i've got two of my other axolotl's from, she still has GFP white lecuistic available which i am really wanting to scoop up.
I'm just wondering how stressful do you think it would be for me to add another (would then be 4 to a 20 gallon long). I see many people (sometimes breeders or per stores which i know mostly do not know anything about axolotls) that keep quite a few together, which from some that i have seen they have been very healthy in size and gill length etc, with no missing limbs or gills.
This summer i would like to get a larger tank or possibly another 20 long which might be easier as i move houses, to add my axolotls to and split them up. but how do you all think they will be coping for now if i was to add a fourth?
anyways i just want to see what your folk's experience has been and gladly looking for opinions and comments.

** note they would all be the same size give or take half an inch

Honestly, I think having three in there may be pushing it--especially because, like you said, they're still growing. I typically keep two adults in a 20g long, but I currently have a third in with them (as of today). They seem much more cramped now...I couldn't imagine another one in there with them as well.

You may be overextending yourself. I also think you are assuming nothing will go wrong while you are increasing the odds something will.

Also, don't assume your college wont enforce their pet rules, unless you obtained a written exemption.

I wouldn't. I had 6 babies at 4" in a 60L (15 gal), and they got snappy, so I would say you would be way too overcrowded.

thanks guys i'll probably wait then.

Good idea. You're already over what I would put in a 20long.