When I saw that pic of the bucket with the spearguns in it I got a bad feeling. I have a strong negative association with that. Read this thread http://spearfishing.world/spea…45-pantojas-accident.html
It looks like a good clean setup. I had a hard time finding a bucket but finally did at office depot. You may be interested in the office depot bucket for the fins. It's the same color (grey) and height but has a rectangular shape. A really good shape for fins as you can have them in two rows, it will take 5 pairs. I reinforced it with a strip of aluminum each side of the bucket as a place to anchor nylon webbing (the webbing is used to tie the bucket in place). This way the forces from the bouncing boat are distributed over a larger area and there's less possibility of the plastic cracking.
Once we started putting fins in the bucket I found it a little time consuming to sift through the fins looking for mine. Almost all the fins have the same black footpockets and many guys are using the black fiberglass blades. Marking the back of the footpocket with a clearly visible sign eliminates this problem. The best marker for this is the Dykem Brite Mark 40.
I too bring a pre rigged spare shaft on every trip. I coil the mono in a tight coil about 3" in diameter (the mono doesn't kink) and secure it with two zip ties one of which also holds it against the shaft. It's a neat compact way of keeping it all together. The zip ties undo easily by biting sideways on the buckle.

