Dude its hard work cleaning out hermie traits and 90% of breeders themselfs wont be able to do it. Some who can will use stable proven males from proven seed strains that have been bred with excelen stability and cross that to the hermie strain and then work your way selecting from huge numbers trying to find the non hermie plants and lock them down to f4 selecting the most stable plants at every stage. Or they will self the hermi strains plants and look for the most stable females in them then cross that to the male from the sstable strain. And then breed to f4 finding the most stable plants at every stage. Its a huge task. To do it keeping the strain pure with no outcrossing is even harder but possible. Your going to be at even more of a disadvantage cus i bet your working with feminised strains so no males and your seeds am probaly already at s2.
Also cookies aint as great as you think, it should of been kept just for flower rather than a breeding plant. The proper clone they first called cookies was a mutated mess. It was extreamly slow veging and would give bannas. The long term effects of injecting it into the gene pool are only going to create issues. And some of cookies sister were bad, as in some were mutated badly, some hardly had any bud, and some would take months to grow to a decent size. I mean why would ppl purposly inject all that into the gene pool. But ppl didnt care they just rode the wave of hype.
You have your plants, just keep them for flower why would you want to breed with hermies. If you was to breed properly with proper plants it should be easy to get as good or better and you wont have to look through 20-30seeds to find one great plant cus if done properly you should have numbers of keepers even in for example in 10 seeds. Whats your goal with breeding with hermies ? Nothing stoping you from making hermie seed strains for your own use, just dont go giving out seeds to ppl saying they are good potent seeds. Anyway just beacase your plant smokes good dont mean its going to create great potent children, to know that you have to do the work and test them. Ther is a difrence between selecting plants for the flower and then selecting parentals.