The straight chartreuse really only works well in cloudy water. In clear water I just accent the tail a little for a bit of flash when that grub tail flutters. If you aren't fishing with at least one rod with grubs tied on then you aren't really smallmouth river fishing...IMHO. I used to fish tubes for years but grubs are just more versatile. You can drag them, dead stick them, jig them, or swim them. I use them 90% of the time in my favorite mentioned colors.
I will be honest, those colors are fairly negotiable most of the time. Sometimes I just melt up some old plastic that is kind of close and go to work. I feel like most of the time the presentation of the bait and location are so much more important. I used to obsess over color nuances, but have in recent years spent that obsessing time learning more about smallmouth behavior and how that relates to my local waters.
I used to carry dozens of colors of each bait. Now I limit myself to three shade. Blacks/smokes, medium greens/browns, and whites/brights. If I can't catch them with one example from each of those categories, then color wasn't the problem that day. Sometimes guys think if they could have just found the subtle shade difference that was hot that day then they would have slammed them. If you aren't catching them with three shade examples, then you need to evaluate the rest of the fishing equation.
In general, I agree with you - we often overthink what we need to catch fish - I still carry a good selection of colors - here's why.
My wife and I fish ALOT of grubs - its our 'go to' bait - for along time, we kept losing 'tails' - we'd get the nibble, react, and pull back a tail-less grub.
We blamed it on 'little monsters' every time - you know - tail biters, smaller fish - gills and the like.
One day - we switched colors - blue -> brown, etc - we started catching decent fish - same area, same everything else - just a color change.
Lesson learned -
If you're getting bites, but not hooking up - the fish like everything about what you are doing EXCEPT the color - and a relatively minor change can help the fish commit.
Similarly - I've had days where "smoke purple" would not produce - but "smoke purple red" would - again - everything else being equal.
