I would recommend going with terminal style fittings and lose the nicopress swages. Even if nicopress is correctly installed or doubled up, you will get galvanic corrosion on the wire strands. My experience is 3-4mm nicopress needs replacement every 2-3 years in a marine environment to ensure safety.

I've run same wire at terminal fitted much longer. These days I run Dyform wire with terminals...though more upfront cost, they seem to go forever (less surface area on the wire strands therefore lower oxidation rate).