I'm probaly way out of touch anyway. I mentioned regulation as I used to work in a feul shop and gensets were very tricky to set up sometimes to always be within tolerance. Particulary if they were to be shipped out and only specific parts used in the pumps. I got caught with one that nearly sent me and few others crazy due to a wrong colour coded batch of springs, company took a big loss on that one. I see a lot of the new PTO sets are hydraulicly driven which is a good idea as speed control is much easier plus modern electronic regulation of output. Good luck with it and I look forward to seeing what you come up with.