In my 4.2m ally pontoon boat, the 2 main things I have found you need are:
1) Off the floor storage for guns - my solution has been a section of PVC pipe rather elegantly cable tied off the rocket launcher. Once set up, we leave the floats attached and in the rear well so if anything goes into the drink we can pick it up again.
2) Off the floor storage for fins, belts and gear. I have yet to solve this 100%, but at present it means fins are slid down either side of the widthways-fitting chillybin, and snorkels/ gloves etc put in net bags, attached to float and stored on top of fuel totes in the rear well. Weight belts go up front in the anchor bin to help with weight distribution
In a small boat keeping the clutter down, and a method for you and others to follow regarding gearup up, and gearing down, is the key.