the nipple type would work, I know here at work we're partial to the Lixit brand, but any appropriately sized one
should work. for the push type, I'm guessing they're the little cup-like ones? prime it for them before moving them in, and they should associate it with water. they might not get the mechanism at first, but if they know water is there, they'll bumble about until they figure it out. If you're worried, you could provide a water bottle when you
feed them at first. if they attack the water bottle, they haven't figured it out yet.