I currently have 3 items—splash plate, wave incense, and sea incense—which all apparently increase the power of water-type moves.
I only plan on having one water-type pokémon in my party at a time, and I don't care about breeding at all. So, based on power boost alone, which of these is the best to use? Is there any general rule for ranking power boosts of these sorts of items?
In case it matters, my water-type moves are Surf, Waterfall, and Brine.