If you have Fabrianno Uno, you will probably be somewhat disappointed with the results, unless you are thinking of a print with high key tonality. It has a quite low dmax, which can be described at best as 'gray'.
If you have the new Artistico Extra White, it appears to be a much better pt/pd paper than the old Uno it replaces. I haven't done any real printing on it yet (other than gum-overs) but it appears that it will make a good forceful pt/pd print if you wish.
I misspoke in my last post. I recommend doing it by weight/volume, and use about 2% or so. If you use warm water (but not real hot) the water will penetrate faster, and neutralize the paper faster. Too hot, and you will damage the sizing, which will make the paper soak up the coating solution like crazy.
There are plenty of other Fabrianno papers, but I don't know much about the others.
The Platine and COT320 are very similar to each other, and in my opinion don't require the precoat. However, I think they may look better with a precoat if you do a single sentizer coat, rather than double coat.
Arches Electric? I'm not familiar with that one. I love the watermarks that they use in these papers. The old Uno had a wonderful stylized cross.