Whitney Need help please.

I have fished with some success but success on Whitney seems to elude me.
I fished Monday from McCown. Very little wind. Crossed the lake over to the Cedron flats and also worked the hump just north of the bridge. Saw plenty of fish on the fish finder several times. I have a Helix 5 fish finder in my kayak. About 1:00 with 0 fish in the cooler I was just about to give up, when these 2 gentlemen stopped me and ask for some help removing some mono from their prop. Easy for me to do, I just went side saddle in my kayak up under their lifted motor and unwound a couple of feet mono. Handed it to them. They put that mono in a ziplock with some other scrap mono, very conscientious, I appreciated that.
They then suggested that instead of the lures that I was using that I should use the Cotton Cordell jigging spoon, the one with the hammered look. They even gave me one. I saw that that was indeed the lure they had on a couple of their rods. And they had fish in the cooler on what what they said was not a good day.
Went to Walmart and bought a couple more Cotton Cordell jigging spoons.
On Friday with a wind of about 10 MPH and cool temperatures I gave Whitney another try. This time I put forth at Cedron. Again I saw bait balls and fish on the fish finder. At one point I saw dozens of fish, nearly blanked out the sonar view. Must have been hundreds or more in that area. I am mostly seeing bait balls and fish from about 23 feet down. Some as deep as 30, but mostly around 25 feet deep, which is where I have been led to believe is where I should expect to be finding them. Went home with an empty cooler.

I have a Helix 5 SI DI GPS and maps.
I have tried a Hellbender/ Pet Spoon
Hellbender / Darting Shad
Hellbender / Hyper Striper 1/2 ounce
Mark Petersen Slab (Yellow) 3/4 ounce
Cotton Cordell Jigging spoon
Hyper Striper 1/2 ounce
1/4 lead head jig with a Pearl tiny fluke

I have tried trolling, slow trolling, down jigging, up jigging, short, medium and long stroke and dead sticking.
I read here where the pros are taking them with artificials.
Apparently I am not doing something right.

I would recommend that you try 4 in sassy shad on a 3/4 oz jig. I prefer the chartreuse and na-na color. Drag it through the fish you see at various speeds until you find what they want. The Dennis Christian method works well on fish close to the bottom. That is a #4 Agila Mepps spinner cast out on a long cast and retrieved 4 reel turns and returned to the bottom. Do the stop and go all the way back to the boat. Silver blades work well for me but Dennis is trying white blades. I have been catching whites and hybrids with this equipment for the last couple of weeks.

the plastic swim baits on jig heads are working right now. chartruse bait on white head or white on chartruse jig are what we use.

I haven't been there in a while, but we normally use these in the 50/50 color
https://rsrlures.ecwid.com/#!/Shad/p/21557766/category=1219201

with these above them with a white curly tail grub
https://rsrlures.ecwid.com/#!/Top-Shot-hook/p/57902682/category=11243214

As far as pace of jigging is gonna just depend on their mood that day. Somedays barely moving, some days in rhythm in good old rock and roll.