It may be a little bit off your intention (and also a little late), but I shot also HP5+ (120 roll) @ EI 3200 and developed in R09 1+60 55mins semistand agitation (30sec initial agitation and then one inversion every 5th minute) with acceptable result. Yes, it is grainy, yes, there is a little less shadow detail, but as Gerald Koch said, either you get the shot or you don't... And I quite like the results...
It may help someone else searching for the development ideas...