New rats, when to switch to a rack?

So I just picked up .2 cinnamon double Rex rats, which brings my grand total to.. Wait for it....

4 rats! Lol I'm planning on keeping them each in their own tub, then rotating my males to get them preggo. I currently house them in large tubs (I know they don't need that much room, but I like the idea of them having a ton of space).

Now I'll have to get two more tubs for the ladies, and at least another one for grow outs, two if I separate by sex (not sold on that yet). Tubs run me about $12, I already have my soldering iron and wire, so I'm good on that.

I have three options I'm weighing:

1. Buy a pre-made rack. By far the easiest option, and I think I can get a 6-tub for $100. Downside is my rats won't have as much space/enrichment as they currently do.

2. Buy and convert 3-4 large tubs. Medium amount of work on my part. Unfortunately, they do take up quite a bit of space, but the rats can have a wheel, toys, etc.

3. Build my own rack. *shudders* I only pretend to be handy lol. I could probably get help in building it though. But it might be cheaper than buying pre-built. And I can make it compact enough to fit nicely in my room.

I'd love some suggestions, or if there are any alternatives that can maximize space yet have the efficiency of a rack. Sorry for the long post. Thanks guys!

I've done it all.
Had huge tubs for a bunch of rats + hides + wheel, medium sized tubs for 3 rat groups, and a rodent rack.
The rack was by far worth it in my opinion and easiest to maintain.

If you feel so strongly about them having a lot of space/erichment, then how about getting a premade rack for your currently breeding/nursing animals. And have a large tub as a 'rest/grow out' enclosure? So your breeding females into the rat rack. Then rotate them into the large enclosure after a litter for a little rest period, then back into the rack for breeding.

Otherwise, I'd do #3.

Brilliant! That should take care of everything, since I already have some tubs made up, now I won't have to waste those. Thanks!