My new addition.

Excuse me for the unprofessional video. I have never made one off of my webcam. I just wanted to share my newbie with y'all.

https://www.youtube.com/watch?v=xX4sF5EZVII

How old?
I can't tell, the telson looks pretty red/brown to me, you say he has some growing, so I'd say he's an adult maybe 5th/6th or even 7th instar. It's hard to tell what instar when they're grown.

Female Gravid/Gestation?
A female will only mate and become gravid once she is full grown. Gestation varies from about 9 - 12 months.

Territory Issues?
Rearrange the enclosure making it different from how it was before and then place them both in at the same time. This makes the enclosure mutual territory. Also make sure they're well fed to prevent cannibalism. They should have a hide each as well. You'll probably notice they might share a hide but it's best to stay on the safe side and for future problems they always have the extra hide.

I can give you a picture of two Parabuthus here laying on top of each other in peace, so it might well be more than possible that Pandinus share an enclosure without problems.

I hear lots of cannibalism problems on this forum with Pandinus species, which leads me to believe they are not as easy as people depict them to be!

Well I will keep them well fed. There are three different hides in the tank (10 gal.). So I don't think they will have a problem with the "dibs" portion. I will make another video on the enclosure.

I just got home from work and checked on them, and they are both in the coconut hide getting along perfectly fine..

Here is another question..

How often can I handle the male without stressing him too much?

I couldn't really say, like you already know, each one has a personality. So not too often, maybe once a month I'd say. Up to you really. Just don't dig him out to handle him, do it when he has already voluntarily left his hide.

Yesterday I had to take the roof of the retreat off of my bicolor. The scorpion sprung right up like a spring. Definately stressful for it.

I dont handle mine, ever... but I can understand you want to hold yours. It will cause stress, minimal stress if you do it gently.. but always stress. How much depends on you.