Thanks for the great info!
When I was looking at my hubs and modified front brake rotors, it appears that the stud holes in the rotors are a few mm bigger than the stud diameter, so it doesn't matter if the knurl/shoulder length is longer than the hub thickness, because it will still fit into the rotor holes if it protrudes beyond the hub. Does that make sense? Let me know if I might be missing something.
 
I'm most interested in your comment about 14.48mm knurl diameter not pulling into the hub easily.
Do you think 14.34mm would still be too difficult? That's the knurl diameter of Dorman 610-460, my second option. If that would still be too difficult, I'll have to persist in searching for something with about 14.17-14.2mm knurl diameter.

EDIT: I ended up ordering a set of 10 of the Dorman 610-445 studs, but the very next day I realised that I shouldn't have. 
It turns out that I'm able to use longer studs than I originally thought, so I'll be using some spares (H&R or ARP) that Julian has.

If you talk to a company called 'nice products' they'll have an answer for you, I've dealt with them many times at work for this kind of issue and they've always come up with a good solution.

i have just swapped all 20 of my studs to extended ones just got them from the local bursons, the knurl on them is 14.4mm and i got them in with just some spacers, wd40 and my tyre iron they went in ok.

Thanks guys!