I'm sure you meant 40" L and not H? That would be just about 2 1/2 x 3 1/2 feet. It might be a little small for two full sized Russians. But if you add plenty of sight barriers it might work out ok.
Yeah i did mean length. I could add 5 extra inches in L but im a bit sutck for space inside. Plus it wouldn't be the full time enclosure, just when at night or when they can't go outside