Fulltilt, it is unlikely that you will get a sufficient sampling on this forum to give you any insight on this. I have read various studies on time to nadir where the median ranges from 20 months to 51 months. It seems to be dependent on the age group, the sample size, the pre-treatment PSA, the isotope used, whether it is HDR or permanent, whether there is other radiation or HT in combination, etc. If anyone locates a definitive study that would be very interesting to see.
In my case, I can't respond to your poll as I am almost 3 years post-brachy with PSA still dropping. Your question is very pertinent, however, to all of us brachy guys...
Tudpock (Jim)