@Syd
M8, the distance of the LNB from centre of dish is not far from what the recommended value in what they call manual that comes with the dish, I think it was about 91cm.
I fully recommend that you try yourself and not worry about what the numbers are.
Take a TV next to the dish , locate 7W and fine tune using a decent receiver.
Make sure prior to that you test your dish with diagonal strings as diameters, say 4 strings, they should not only meet in the middle within less than 1/2 inch , they MUST be on the same level, if one or two is 1/2 inch above or lower than the rest of strings then the dish is NOT level, you would need to sort it out before testing for signal, this makes HUGE difference.
After that, the LNB/feedhorn, distances, Skew and all those are simply trial and error and no more than fine tuning, I wouldn't worry too much about that as the main thing is to make sure the dish is in shape then you can take your time with LNB etc.