Hi Chris, my sugarbeet!
I use the vari2 and have for nearly 18months now. It has served me well with a 75psi surflo pump. I haven't had a day short yet. But I do only run 1 hose off it. For a year I ran a huge 100metres of half inch hose from it no probs. Now I am converting to minibore, not microbore. Minibore 8mm dia. I have turned the inside notch on the vari2 up a couple of notches. All ok.
I have to admit, I think the minibore 100m hose is putting a bit of a strain on my 75psi pump, maybe even battery, but I'm charging up to keep on top for now.
maybe that will give you a bit of info?