Thanks the the details. I'm using Xpress colors myself, and I use their medium but it's promoted as working nicely with water too. I should try it to tone down some color I find to intense as it.
For wash I've been using flow improver. It works pretty well. For the others it's been speed paint and Xpress with Vallejo medium. For the Syennan I have used no medium because I want it intense dark red.
