Here's another reusable and permanent possibility, but with a little extra DIY effort required...
(there was a url link here which no longer exists)
(Note that the correct post is #42, not #43, which seems to be the one displaying for me.)
(Also note that the product links within the above post are now broken, see below.)
I made up a couple dozen of these one afternoon and have used them on-and-off for years. Because of the mesh design the solutions are able to fully reach and remove the anti-halation dye from the back side, as the sheets never touch the side wall of the tank and there are no rubber bands.
And because each sheet is completed enclosed, there is no damage from loose sheets crashing into each other. They are easily loaded in darkness and three will fit snugly into a 2-reel 120-size stainless steel tank.
For your DIY efforts you will get perfectly evenly developed sheets right out to the edges, when using standard inversion agitation, every single time.
However, I should also mention that another APUG member did contact me saying he had noticed fine scratches on the base side of his sheets when using these cages. Presumably that would mean that the ABS plastic is harder than the film base, and so leaves marks.
I have not seen these marks on my negatives, but it needs to be passed along as a possible issue anyway.
Ken
Updated product links that will eventually break as well:
Frost-King Gutter Guard
Thomas & Betts SF100-18X ties