When they fully drop leaves and go dormant, you can cut them down. Leave about 4-6 inches of stump above the soil level. Your females will produce suckers at a distance from, and right around the trunk. I personally recommend selecting some at a decent distance from the stump, in addition to selecting a few suckers from as close to ground level around the stump. Backup in case the stump gets an infection. The male trees will only put out suckers in extremely close proximity to the stump. Just try to select the best ones. This may be different in the other two North American persimmon species groups, but I'm not sure. Each group has a different ploidy level, meaning they have different numbers of chromosomes and cannot interbreed. I have however heard that the different groups count as pollinators, but crossed seed will be stunted and atrophied.