I am a little late to this discussion so I will try to cover several items at once.
My boat is a C30 Mk2 so very simular in almost every way. In your first post you commented that the small screws were pulling out of the deck. On my Mk2, all of the stanchion bolts are thru-bolted. Some of them can be an absolut bugger to get the nut back on once you remove them for rebeding. I printed these nut holders just for doing this job. It hold the nut captive until the threads come all the way through the nut and then the threads push the holder off.
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I had two screws that were completely impossible to get the nuts back on without cutting out significant access holes inside the boat and that was not acceptable. In those cases, I drill the holes out larger and epoxied in knurled brass ferrules so that the screws were attached to brass threads strongly anchored into the toe rails.
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I have a midship cleat that I use for my spring line that is at the widest part of the boat.
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I used to use the midship cleat when docking but found that it would turn the bow into the dock when used to stop the boat because it was too far forward. I now use a dock line that has the loop dropped over the primary winch. From this location, a line dropped over the back end of the dock cleat will form a single line tie that perfectly balances the boat parallel to the dock. When I am single handing or with experienced crew, I use a line with two loops and 6' between the ends. with one loop on the winch and the other loop on the stern dock cleat, I can then bump the boat into forward and it will pull against that line and the balance between the line and the prop will pull the boat over against the dock and stay there with no other lines as long as the engine is running.
With less experienced crew, I will use dock line over the winch and tell them that their job is to hook that line around the back end of the stern dock cleat and pull on it when I tell them to. With new crew, before I go into the marina, I tell any crew that will be leaving the boat "Your job is to step off the boat and pull on the line when I tell you to. You are never to jump from the boat because that will push the boat away from the dock. You are only to pull on the line in your hand and not touch the boat. If you try to pull on the boat instead of the line, you will be leaning too far over the water and likely will fall in. You are not to push to boat away from the dock because the whole point of docking is to touch the dock and the reason I have all of those nice fat fenders out there is to protect the side of the boat from the dock and they do a much better job at much lower pay. If I am not close enough to the dock for you to step [NOT JUMP], I will back out and approach again."
I then tell them a story about one time when a crew disregarded this order and jumped off just as we got close, stumbled and when headfirst into the 50º water between the dock and the boat next to me. In the time it took him to finish his plunge, turn around and reach the surface, I had backed down to a stop, stepped off the boat, picked up the dock line he had dropped and have my other hand ready to grab his and haul him up on deck. Between his chattering teeth, he said, "I guess I shouldn't have jumped." Ya think!!!!