No more
novels after this - promise!
I just can't help myself. I got to modify baits weekly especially when the weather keeps me indoors. Retired, I can only fish some of the year - no more ice fishing for me - and must stay in touch with anything fishing related. (No TV shows thank you.)
Molds are okay but unless I sold lures made from the many I have, I can only use so many of the lures poured. Thought of selling them, but not worth it nor the
air pollution in my basement from 275 degree heated plastic. Modifying soft plastics is the closest thing to making something no one sells yet catches fish
consistently.
Now, for a mod to work,
action speaks loudest to fish. That is, the way a lure moves using one or more retrieves and speeds. The thing that defines all of the thousands of lures ever made that provoke fish to strike, is action and action is dependent on many things that involve lure shape and bulk, tail shape and other moving parts. Color can be important when it emphasizes those physical elements and contrasts with the background.
Are fish fooled by lures into believing they are a particular prey animal? Don't know/ can't know. All I do know is that
certain lure actions have proven themselves since the first lure caught fish.
Match-the-hatch IMO is myth yet an art form when it comes to all of the fly tyers that produce specific flies patterns. But the action of flies is the same regardless of pattern or color.
What are examples of lure actions that get strikes but that also crossover into other lure types? Here are a few:
Remember the Zara Spook? A surface
waddle waddle waddle using rod tip jerks. But guess what? I've found a shape that does produces the same action but subsurface. I call it the bulb or rounded tail:

Even sunfish jump all over it:

Here are other versions that produce the same action:

The
waddle is key! Why? Your guess is as good as mine.
Another version of the waddle / jerk action is the jerk worm but not just any jerk worm. I found out that Yamamoto's Kut Tail worm's action was incredible when jerked back and forth -
zig zag if you will. Fish jumped all over it from the surface to mid-depth in 8'.

The worm is poured using the same mix as the Senko - not too buoyant/ not too soft.
The tapered body-to-tail is also key to the lure's jerk action.
Another that has the same action is the
Softie worm (note, it
isn't a mod but only used as an example of action-per-shape) :

Same taper-to-tail shape and plastic that is a bit firmer.
Speaking of the Senko, what about the Senko action when wacky-rigged? The weight of the plastic allows the dual-tip action to
quiver & rotate on the drop. The same action can be applied using the rod tip twitch at different depths. Again, even the smallest stick wacky-rigged can produce the same action or various versions of it. Here's one:

This one can be wacky rigged or used like a quivering stick:

Another wacky rig shape, I refer to as
whisker because what it looks like
attached to a fish's lip.


Any of the wacky rigged shapes exhibit far more action than the lumbering Senko sinking to the bottom. In fact, I produce the action at mid-depth and rarely let the lures drop all the way down.
Note the various species that can be caught on
any of the above and it's all because of
the combination of rod tip and lure action combined. There are many more but you get the idea.
Take all of the above for what it's worth from someone not inclined to use live bait or store-bought lures (except the many classic hard and soft plastic lures stored for 30 yrs. in my basement).