My 40 Ocean came with four in the cockpit. There’s two in the forward corners of the cockpit floor just outside the companionway and two on the floor to each side of the binnacle. They’re U-bolts with backing plates and bolted through. You can either clip on directly, or have a jackline running between the fore and aft ones. This layout works well and I’ve not yet stubbed my toe on either of them, indicating that they’re well placed 😀

    One improvement might be to put the aft ones in the aft corner of the cockpit, so they’re behind the wheel. That way, when using them with jacklines, your tether won’t rub on the wheel. It’s a very minor thing though.