there are alotta strains out there. Tasmanian have the highest potency opium.
I think another strain from chezc/urkraine area has the highest yield.
The poppies should just go into flower on their own, its almost better to not pay 'em too much attention, except for watering and fertilizing them reg. One day you'll see "hey! some seed pods" let them mature a bit, cut em up and smoke it.
However, if you cut the pods, don't expect any seeds. Maybe leave the biggest seed pod, and use that one for your next crop and just work on your own genetics.