Anything sitting up high will give you a high center of gravity. 1 gallon water = 8 lbs.
You may consider a bait tube, it will be extra drag but you can keep 5-6 macs alive most of the day.
The other thing, not really sure how you feel cutting into the kayak but it may be possible to rig something like the live well hatch in the Malibu kayaks or something like this with a bigger compartment
https://www.amazon.com/dp/B004CG9N1U...a-315981559108