Brian,
Did you buy your Rollo Pyro from Bostick and Sullivan? When I got mine about 2years ago now, they included a green sheet of instructions. I recall they recommended 8min at 68F in a Jobo. This time seemed about right. the negs were a bit flat but that's always been my impression of HP5...

In terms of metering, I do the same - 1/2 the ISO for my EI and place important shadow on zone IV...

Take care,
Tom