We used the Aubrey pulls (love them) throughout our kitchen. We used 4-inch pulls on all the doors and 6-inch on all drawers; our pulls are polished nickel.

You can't see the screws on the inside of the drawers. I did have a concern about finding replacement pulls that would cover the screw holes, if that ever became necessary or desirable.

Our widest drawer is 30 inches and I think the 6-inch work fine on them. We wouldn't have gone longer since I wanted to use the same size on all drawers and we have a couple of 15-inch drawers where a bigger size would have looked odd (at least to me).

Our kitchen's not fancy but here are a couple of pics.

In this picture the wide drawers are 30 inches and the narrow are 15 inches.

I'm not sure this picture really gives you a sense of the pulls but here is our other wide-ish drawer (on the black cab).

A very belated THANK YOU for the info and the pics!