What decides the success rate of facial/beard hair transplant?

Will the transplanted hairs look like the facial hairs I already have (they are very very small and fine. I have very few of them…) or will they appear like real thick facial hairs? I'm afraid that after doing a beard transplant, the hairs will grow like the one I already have, which mean that they will look very thin and small. Do you also recommend the use of minoxidil after the transplantation (maybe start using it one month after the transplantation ?) ? can that enhance the results ?