As a co-angler you'll probably be fishing the shaky head a lot. I own many different brands, acquired in the pursuit of a perfect shaky head. That quest is no where near finished, but I understand what I am looking for now. Here is some stuff to think about. Many people think shaky head fishing as a finesse technique and it is - kinda. Be mindful that if you're fishing a lighter weight head from the back of the boat, the boater will often move the boat before your bait sinks to where you want it. Just a fact of tournament life as a co-angler, more often than not the boater keeps the boat moving.
Very occasionally, the fish will want a swimming shaky head and in that case you're golden. Most of the time they don't. The answer here is to go with a heavier shaky head. You can go 3/8 oz on 8 or 10 lb line. That is one option. That allows you a better chance to get your bait to the bottom and work it for a moment before the boater moves the boat. If you have to choose between a head that is better at dragging or at hopping - go for the dragging, as you will probably be dragging your bait behind the boat quite a bit. Chompers makes a 3/8 oz head that I like quite a bit, but there are plenty of other styles out there. Recently I got some 3/8 oz finesse heads from Megastrike but I haven't fished them that much yet.
What I eventually evolved into was a 7/16 or half ounce head fished on 14 lb fluorocarbon. Bait casting gear handles this weight line better than spinning gear. Another option to consider might be a jika rig. I make my own and the ones I use weigh out to around 5/8 oz. Depending on what hook you puts on them, they fish shaky worms, magnum shaky worms, creature baits, lizards, whatever. Advantages to these are that they always drop straight down, which is handy to know when you are targeting objects rather than areas and they are pretty heavy so they get to the bottom relatively quickly. The advantage to this becomes apparent once you've fished as a co-angler a lot.
Tx. rigged football heads and Biffle bug type baits are other options, I'm pretty sure that other guys know more about the ins and outs of these baits more than I do. Last couple of years when I've fished out of some one else's boat I've focused on the heavier jika rig.
Fishing out of my own boat, where I've got control of boat movement, I've had a decent amount of success throwing quarter ounce Brewer Slider heads and5" paddle tail worms on 10 lb line. Generally I'm throwing this boat into water than is more than 3 feet and less than 10 or 12 feet. Any deeper and I feel like I've got to wait too long for the bait to get to the bottom.
So there you've got it - current thoughts on shaky head/soft plastic/co angler fishing. I've never fished on any Texas lakes so I don't know much about how this will apply to your situation.
Option #next would be to check out the gear that the most successful co-angler in your club fishes and fish like he does.