Mine is laughably simple and portable. And everything is done in the tub of our spare bathroom.

First, a tallish 1-gallon Rubbermaid cereal keeper or open tray containing HCA.

Then I use a 5-gallon plastic mop bucket, somewhat rectangular in shape. I hang a recirculating aquarium pump off the side. It moves the water around but is not intended to filter it. Badda-bing, that's it.

I give the prints 10-30 minutes before dumping and refilling the water. Two or three cycles and it's done.

Recently I've added another bucket and pump to make the process a bit more efficient.

The recirculating water keeps prints from sticking together. I'm comfortable with up to three 8x10s, several smaller prints or one 11x14 (gently curled up) at a time.

Anything larger, heavier or even slightly awkward to lift and move frequently is out of the question for me. I use the tub in the spare bathroom for fiber print washing sessions so I must be able to easily lift any archival washer for every session. That rules out all of the alternative homebrewed washers such as glass aquariums, etc.

Right now I'm torture testing a fiber print run through this setup. It's been taped directly to a sun-facing window for three months now. I plan to leave it throughout the winter since condensation is likely to occur some days. If it survives I'll declare my homebrewed archival mop bucket method officially safe and sound.