"I think it's kinder to get a small one and let the tank limit its size than to get a large one that will be miserable and possibly die in too small of a container"
You'd rather it be stunted, then have something too big in too small of a space? I have no idea about cray fish with that... But if it were for anything else I'd be heavily worried for any fish under that care! Most critters outgrow whatever they are in, either by body, or by organs. Stunting causes many problems - especially with aquatic animals. It can make them more prone to diseases, more likely to die younger, and in some cases organs shut down sooner...