[Arn0]

You got it right Sosidge, it is 2 holes and not one. I don't know in what I was thinking of but it is two and not one hole as mentioned. Sorry for that!

The calculation for laminate is more that just calculate surface area even surface area are part of the mathematical model.

I did not measure any piston, the gentlemen mentioned at the bottom of the PDF did - thanks again! I can't do so as I run pan car.

Lee explain the main idea, plus details in fact. Fluid behave differently to each condition. The hole edges have an influence as the number of holes and the distribution.
The edges get a influence on the shape of the flow through the piston, the round edge make the fluid kind of sticking to the round as the square edge create more turbulence. I might try to get more details about this point.

So, those calculations are theorical but, as probably already said, there is a good amount of testing for whatever the vehicle is; car, bike, truck, both racing or street legal one, the same apply to RC.

The chart is made for off-road now, but it can be easly be made for on-road. The point of this chart is to try to provide some reference point for drivers who swap the original shock for other brand or to get some reference point when you try to copy-paste a setup and you do not use the same shocks as the one mentioned on the setup sheet.