Wow - loaded & open question... Different shapes of jigs will do different things and create different actions. Depth, current, bottom, casting, and price (important due to jig loss
) all will play some heavy factors in which jig you use.
For schoolies, I tend to use an upperman style bucktail in relatively shallow water but I switch to a couple different types when using plastics, sometimes a smaller ball jig or a bullet head or Kalin's.
I don't do much deepwater jigging but when I do, it's usually a bigger Smilin' Bill.
For hook lengths, keep in mind that the longer the hook, you run the risk of bending on a bigger fish if it gets dome leverage or if the hook is not up to snuff.
There were a couple articles on this, one from Bill Nolan & the other from Saltheart...
http://www.striped-bass.com/Articles/saltjig101a.shtml
http://striped-bass.com/Articles/wwalltactics.shtml (but I can't find the one that had better detail
- sorry )