HR and Tempo run

I have a resting rate of 50, and a max of 180. this gives 70% as 141 and 85% as 160.

So for my tempo I warmed up for 3 mins ran a mile at 60 to 65%. At one mile I picked up the pace to get me to 70% which by two miles had become 80%. From two to three it averaged 85% but as it also includes two hills it did peak at 90% for a very short time. I them slowed down to the pace of the first mile for the last mile - my pulse stayed at about 70%.

So did I get the pulse rate targets right and did I get the tempo concept right?

Any help will be gratefully received.

Sounds about right, Mij. Can you set zones on your HRM? What i do is go out slowly, glancing at monitor to check that i'm below 65% (or whatever). Set the monitor for the zone i'm heading for - say i want to do a tempo run at 85%. My tempo (to use your figures) target would be 160 bpm. so i set the zone for 157 minimum and 163 maximum. The target figure is in the middle. Then as i reach the end of the warm up i switch on the beeper and start running harder. When the beeper stops beeping, i'm in the target zone and just keep running without beeping which may require slowing or speeding up a bit depending on the levelness of the road.
(Am i making sense?) At the end, i slow down, switch off the beeper and jog the last mile home.

Thanks - the question I still have is should I try to run the full 2m at 85% or was I correct in building to that point?

My HRM has target zones in 5's so if I followed your way I'd set it 155 to 165, but go to that rate after the first mile and hold it for two miles before coming back down for the last mile.