Some truly excellent info in this topic.
I'm not much of a jig fisherman....even though I probably have 1500 of them
That said....I will add to something Tom stated about jig weights...and marry that to what Jim said about trailers.
Hook size CAN make a difference in a jig...and it can affect the drop rate of the jig / trailer combination.
For example...let's say you have 2 jigs.....both with 1/8 th oz of lead. One has a size 6 hook (small)....the other has a size 2/0 hook worm hook.
The larger size hook would allow you to to use a larger chunk of plastic. And many plastics have some bouyancy to them...so a larger one sometimes can sink slower that a smaller one...as it displaces more water.
Styles of hooks ALSO can affect what applications you can use a certain jig for.....and shape of the head makes a difference too.
Last but not least....sometimes companies will market jigs with a resin head on them...which make them considerably lighter in relation to a same physical size lead head.
I was able to pick up a bunch of these on closeout from Cabela's a few years ago. STILL haven't tried them yet....but this topic reminded me that it was and still is something I'd like to do.