Generally, I match the hook size to the fish, rather than the plastic. Most plastics can fit a range of sizes (within reason of course). Generally you'll want the hook 1/2-1/3 of the way down as a very approximate guide. Theres no set defined rules. Just make sure theres enough tail for movement, or for longer plastics, make sure that the hook is at least some of the way down the body, and not right near the head.

Just remember that the gauge can vary as well. I've seen a few people have jigheads bend out. The hook size was fine for the fish, but the gauge was too fine, even though they were using light gear (big fish munch them up).

Good advice hlokk, i have had a few hooks die on me too :(

and remember that you can always trim the plastic down  to to match the fish which i often do when it comes to 3 inch jerkshads and wrigglers when i find that the fish are not quite reaching the hook.

I do this religiously with herring and i doubled my hookup rate as soon as a did it

It can be done just by biting the head, but lay the jig head next to it to see where you want it to go first.

.

are very good because of the keepers on them and the hooks ? Haven't seen one myself yet.

The squidy heads have pretty good hook keepers but crappy guage hooks, and the nitros are quite pricey, have a good hook but average hook keepers, it all comes down to personal preference but i have a mix of all brands and designs so i can decide when im there.

TT head hunters all the way, best hooks, sizes, bullet head makes for perfect action etc etc etc