After my 3-month period of retention, I have concluded that around once every 2 weeks is a good orgasm period for me, so here is the plan:
Coin-toss once a week: orgasm if 'heads'. Thus an average of once every 2 weeks.
I have just run a computer simulation of this, and noted that runs of 10 tails sometimes happen, which is 10 weeks of course - but this is very rare.
To dissuade me from extra orgasms, an unplanned one is followed by 30 mins of a seated pose:
this is difficult, yet good for will-power.
Then comes a month of retention.
Actually, having done 3 months, I'm fairly sure that there willbe no accidents!