When should I move them in?

[SerpentSteve]

I currently have 3 retics with the male just over 5 ft and my two girls about 1ft behind him. I'm having a family member build me 3 8ftx3ft cages for them and was wondering if i could move them in in a couple of months when he's done or should i wait till they're a little bigger? Although I've never seen it personally in my previous snakes, I've read and heard from multiple sources that they feel more secure in smaller cages so it made me wonder if I should wait and gradually move them to larger cages.

Thanks