Cage size for juvenile Russian rat snake?

[kudzu]

Last week I got a Russain rat snake baby. He (or she) is currently housed in my Brooks kingsnake's old tank. While that tank was fine for my kingsnake for his first year with me, it seems it won't be big enough for long with this new active, growing boy or girl. Also, with this tank we've got the "big giant hand" problem again. The noise of opening & closing the sliding lid combined with the big hand reaching down at them, is just scary for the baby snakes. Will say, the Russian certainly recovers a lot quicker than the Brooks. So far I'm loving the new guy's temperament! But I'd still prefer a front door so I'm less likely to scare him.

What would be a good size for a juvenile Russian? He seems to be making use of the whole tank, especially his tree & greenery, though it's only 12" high. I don't want to put him in a huge cage yet, but would like something that could last for the next year.

Right now I'm thinking, 24"l x 24"w x 24"h. Maybe it won't be too big for a wee baby, but will to give him height for the climbing he seems to like. The hope is to give him room to roam comfortably for now & the upcoming months until he's ready for something larger. Once he's outgrown the cage, it can be used for a gecko.