My experience does not really directly answer your question, but when I looked the other day what a Y to J (cash) upgrade on an existing ticket would cost (I used the ‘upgrade using cash’ option on MMB), I noticed a ‘switch’ with the label ‘Use BR points’. When I switched that on, I could see how much the cost of the upgrade would be using most of my BR point balance. Was not a huge saving but I’ll probably use it when the time comes. Guess I’ll only collect tier miles and Skywards miles pro rata to the actual cash component.
If I remember correctly, the value seemed to be around $0.05 per BR point, but I may be wrong and the value might not be fixed either. In that case, I fear that 11K BR points won’t buy you a ticket outright, but it should give you a ‘discount’.