My partner and I troll a lot in tournys here.
I highly recommend Bee-Ready holders. Excellent quality and they stand behind the product like no one else.
Look under Rod Holders - Crappie Rods, Crappie Jigs, Catfish Rod, Catfish Rods, Fishing Rods
When we are using the 2 seater up front we only
use 3 rods each as well. That's plenty.
We are allowed 8 rods in the Texas tournys and we sometimes
do put an extra 2 sets in the back sometimes.
Here is a modified version I use that has been very successful.

I rig up a bunch of leaders and can be back in the water pronto.