I asked Do-it molds the a similar question. This is what they sent me.
You are absolutely right. The three jig models that you have mentioned
are very similar with only slight differences. Their wide design helps
to keep them from rolling or turning on their side.
Weedless Sparkie Jig: This is probably the widest of the three. You will
notice that the hook eye on this jig comes out much more toward the
front than the others. This forward balance lends it self to dragging
the jig on the bottom or swimming the jig through the water. Some people
prefer y-guards over fiber guards. This mold will accept either.
Style "S" Bass Jig: This jig is slightly narrower and the hook eye comes
out a bit higher on the jig. The balance on this jig allows the back of
the hook to rise up, off the bottom when the jig is "rocked" similar to
a Football Jig. It also accepts either fiber guards or y-guards. The
Eagle Claw style 730 hook for which it is designed is one of Eagle Claws
strongest tempered hooks and sports a slightly larger throat than the
O'Shaughnessy style 410 for which the Sparkie Jig is designed.
The Arkie Style Jig: This Jig is very similar to the Style "S" with some
small improvements. It is slightly wider, and tends to fall more slowly
and horizontally because of this. The double holder collar tends to hold
skirts and plastics or buck tails a little better than the old fashioned
ball collar of the others. The Mustad Premium Black Nickel hook is one
of the strongest on the market. The turned eye on the hook helps with
hook ups and lends a bit more power to hook sets.
All three of these jigs are very good when fished in cover. Which jig to
use is purely a matter of personal preference. At this point we consider
the #3387 Arkie Jig mold to be the best all around weedless jig of the
three. We hope this helps.