I have a 12 ft. female and a male at /- 11 ft. They are both at least 7 years old, and I've had both for the past six. My male has shown great interest in breeding, my female none. I grew them very slowly, and I've gone to some length to avoid obesity. That said, my female is considerably heftier than my male.
The female was probably CH, the male imported at around 6ft.
I introduce the female to the male's cage. Its an anxiety producing event for both animals, and I more-or-less supervise them. The first couple of times they thrashed about a fair bit, the last couple of times they found a corner and stayed there. I didn't witness any copulation. I'll try again next fall.
Fantastic animals though. It'll be a shame if they don't breed, but even if they do there just isn't much of a market for them. It will be saturated pretty quickly if many of us who are trying actually succeed.