what to use as a male

i have 4 kush plants started.all are fem seed.i would like to make a few seed from each female .what would be a good strain to cross with them.2 are og #18 and 1 kandy kush and another.never tried getting seed from a fem plant.i heard og #18 is great so i want to make seed as close to female as possible.all help would be appreciated

Cross them with some bag seed males. That will reintroduce some 'wild' genetic stock and keep your offspring 'naturally' healthy.

and if you want to get something close to your original mother, just keep back crossing her offspring to her. your f1s will be 50% kush, f2s 75% and so on. i like hybrid vigor and all, but in a case, like yours, where you're trying to get a specific type of plant, i don't understand breeding with something different when logic dictates you'd want something as similar as possible. i've never understood trying to preserve a sativa by polluting it with an indica. if you want to stay as close to it as possible, find a DIFFERENT sativa. i'd think the same thingin your case as you're specifically looking for kush traits. you might not get much hybrid vigor out of a different kush line cross, but you'll get closer to your goal right at the start, and might even find you like the other one better.