When to BD?

Let's say you can only BD 2 maybe 3 days fertile fertile week. Which days would you choose?
Day of + Opk & day after?
Day before expected + Opk & day after the +? 
Or 1 day earlier in fertile week and day of +Opk?
Thanks! I think I'm excepting too much from the hubs. We try hard as soon as we get the green light. Then by the time I reach peak fertility he's done:(