Good ratcheting cargo straps would be a good way to cinch it down. Cleaner, as neat and a whole lot simpler than what I did. Some of those ratchets are available in SS although if the bilge is dry plated steel will last for years.
I use those to strap my batteries down.
Years ago I built and installed our holding tank.
I built a curb all the way around the tank bottom so as long as it is held down it cannot go anywhere.
To the platform I added 'U'bolts mounted through the curbing and then used 1/8" SS wire running rigging with nicropress sleeves and thimbles for the loops and a couple of turnbuckles to adjust tension. I check the turnbuckles periodically to be sure they are still snug.
I did add a piece of SS angle across the top, front and back, to carry the load of the wire so there is no direct contact of the tank. I grooved the angle so the wire makes a radiused turn rather than a sharp bend.
I don't think the perforated copper strapping would be good enough for this though unless you had a really high curb. It is available in pure copper as well as the plated steel but without some thought would be difficult to rig a tensioner that would not tear the holes. It is intended for light loads. Can be done but there are better ways and the cinch straps with ratchets are one way. Just get ones, straps, with a decent load rating.