Congrats Brand0n...The addiction has started...LOL
To answer your questions, here's what I like and think of different style of jigs:
Football Jigs = Rocks
Arky Style = Timber
Casting/Flipping = Weeds and Grass. Casting style jigs have a light hook, so I would use in sparse vegetation and flipping would be great for the thick stuff.
The above are just guidelines for me, I don't mind using ,say, a football jig for a casting jig situation or an Arky in rocks, but the list is really how I use them and, for me, make the day that much more enjoyable.
I generally stay with 1/4 oz and 1/2 oz for the most part heavier if the thick stuff is really thick so I can punch on down thru, so you 3/8oz jig is, IMHO, a good tweener jig and a very popular one at that.
Tom, how's that arky serving you?