That is a good plan. I posted yesterday, but I must not have submitted it.
I would guess that the Tinc that passed was being bullied by the larger of the two. I have seen this a couple of times with a same sex pair... particularly two males. When they start to mature, the dominant one will push the other around, take most of the food, and stress the other out to a point where they may not eat.
I would get an adult female to go with your already dominat male for best chances, and good luck.
Also, you are most likely going to need to find a breeder that has adults for sale, or go online for an adult female. I have not seen them in stores around here, but I bet the critter could order you one.