Many years ago I became a big fan of Mr. Twister curl tail grubs for smallmouth. 1/8 oz was the best jig weight for swimming jigs in small rivers that had a lot of rocks. That lure design was also good for lakes less than 20' deep and allowed for a lot of water to be searched. The problem with curl tail and shad tail grubs is that they must be worked at a certain speed for the action tails to move which is okay when swimming them, but not okay when using a super slow retrieve with pauses.
1/16 oz unpainted ball head jigs have been my best all around jigs for use with non-curl tail grubs. Straight tails have the advantage off being retrieved super slow parallel to bottom, demonstrating a slight tail quiver action that fish are very sensitive too. For me, lure action is everything - the more subtle the better. But what I've found in the last month as water temperature has fallen to the 50's is that slower is never too slow for inactive fish. That's where 1/32 and 1/64 oz jigs come in.
Plastic has weight and when using a light jig, provides for the casting distance needed to cover water. Some plastics weigh much more than others such a Gary Yamamoto's Kut Tail Worm - one of the best multi-species baits I've ever cast. Other bait designs aren't as long or as heavy and the plastic isn't the same as the worm without the salt for weight. But still those lighter plastics still cast a decent distance using light jigs as long as the line is smooth and has no memory curl. (I use small diameter braid after finding out how much easier it was to cast light lures.)
What has been a big surprise is catching fish in shallow water 4-6' when shown on the fish finder after jigging straight down in line with the transducer. You would think the big boat drifting slowly overhead would spook them, but when a fish is provoked to strike, that fish was susceptible to vertical jigging a light lure. A larger lure with a greater action tail may not have worked, but I do know that fish that strike again on repeated casts have become very aggressive and usually do get caught.
Nice thing about finesses lures is the number of lure designs that catch fish anytime anywhere. I keep finding more every time I fish. Shortening lures or modifying them in other ways keeps me from buying more, plus I pour some of my own in colors I have confidence in. It's unusual for me not to catch at least 40 fish per outing / at least five species. I've had plus 120 fish days when I was able to find tight schools or fish closely scattered together around my boat along shorelines or over flats. The light jig and grub is my confidence lure combo and in all my 40 years, I've not found another as effective for smaller species fish. But still, since last year I've still boated six catfish from 3-7 lbs using grubs and a 1/16 oz jighead as well as a few bass over two pounds.
Getting back to the importance of jig weight - it does matter depending on depth and speed fished and by speed I don't only mean drop speed. Granted, I use 3/4 -1 oz skirted jigs to punch heavy cover and get reaction strikes. But for swimming or vertical jigging, there are times when both do better using smaller and lighter lures. Would I use a 1/8 oz jig head with a Kut Tail? Most definitely not ! The beauty of the design is the superb body action caused by rod tip twitches and pauses. Yesterday I got strikes on it other designs didn't - in the same area. The key was rigging it on a 1/32 oz jig head with #2 hook.
Water temperature averaged below 56 degrees but the bite was strong when fish were found with my lures.