you are not going to be able to just screw off
the old spout and put in a hanld held pull out sprayer..
it is not that easy
and this is the real world we are talking about .
the best one you can buy is made by Delta....
we have a few collecting dust on our shelves but
they take another two holes in the tub ledge to make them work...
it is a pretty complicated mess to install even on the original rough inn ..