My friend, who has started breeding them, was answering similar questions to these when I was on the phone with him last. It seems a lot of what he has observed within his own collection, they were more 'defensive' than 'aggressive'. Very much a 'Leave me alone!' attitude. Aggressive is actively acting out against you, even if you aren't pressing it. Defensiveness is when you invade their space and they don't feel comfortable about it.

When they are in their cage, they are going to have moments where they are defensive. They don't want you to bother them. But apparently once they are removed from the spot they are 'defending' they tend to settle down moreso.

I had a bird like that before. Most 'aggressive' bird in her cage. Laid my hand right open before. But, once she was out, she was the sweetest, most adorable little thing.

Of course, I'm just going off of second hand information here and do not have experience myself. However, it does make sense. Snakes don't act out unless we present them with a stressful situation, or when we are seen as a threat or bothering them.

Another risk with young GTPs is how delicate they are. They are quite fragile, so that's a pro to the adults. But if you want to watch the color change, I don't see how that is a problem. Especially since you are expressing wanting more of a display animal than anything.