This is my biggest boxwood i have. I dont think its considered a twin trunk because they are not in the soil. One of those branched has to go, just spending some quality time deciding which one stays and which one goes.
It's a nice tree, I just haven't had any luck with boxwoods. I don't think I'd cut one off, I'd probably just leave it and develop what you have. If you do decide to cut one, I'd wait as long as possible to assist in thickening the trunk.
Honest it looks healthy and that is a great start. Keep it growing for an entire year and search images of old southern oak. With a couple of years of growing and proper branch selection and wiring it has a great start at that style. I am thinking it actually darn good but would need to see some eye level photos rotated a bit for each one.
First time I noticed this post, busy weekend in so many ways...