Ok u can do two female but try to put caves at the other end of each the tanks. The cave u wanna use should be just enough to fit both plecos but not big enough that theres room on the sides if they were both in the cave. It should be just enough for them to cram in there, also be deep as they will lay the egg in the deepest darkest part of the cave. The male will breed with both females, but there is a chance of him just end up choosing one and they chase away the other female.