Why restrict himself so much by looking for a low mileage car. It is no guarantee that it is going to be better than a car that has done average mileage and been properly looked after. I would be more worried about the last couple of years history rather than it had its oil changed at year 1.
Tips were not that popular so he is working in a smaller market. Buy on condition not a pre-determined wish list, that way you will get a good car. The reason I make this point is just look at the number of new 993 owners who have either bought on a budget or other limiting factor and you will see them posting a few months later about all the things that are wrong with the car. There is no better way to find the car you want by going out with an open mind and driving the thing. I occasionaly go and look at 993's that are advertised as full history, immaculate condition etc etc etc and as yet have not found one that lives up to the description and that includes alleged full OPC history.