Haven't read the article, but would have thought that provided you use a good deer bullet, rather than a varmint or target bullet, the deer probably could n't tell the difference between being hit by a 6mm PPC and say a .243 Winchester.
6mm PPC is a bit slower than the .243 winchester, but not sure if that is a bad thing - rather than explosive bullet performance, you would get better more controlled expansion and carcas damage. Would it have enough case capacity to push 100gn bullets at a reasonable velocity to make big deer legal in Scotland?
6.5 x 47 - 120 gn @ 3,068 fps - any difference between that and a 25-06?
But they are all very accurate cartridges and accuracy is no bad thing when shooting deer - after all shot placement is far more important than the actual size of bulletor its velocity. A .243 in the right place has killed a very large number of stags and is used overseas on much bigger game. But a gut shot Roe with a 375 H&H will still go a very long way.
www.6mmbr.com gives all the different ballistics.