idch, I'll give you my opinion on the harness, as thats what you actually asked about.
First, how well can you solder?
If you know how to solder, then in my opinion, you would be better off doing this yourself.
I do use fancy caps, and I understand that they probably don't do anything more than the cheap caps, but I like em anyway.
One thing about RS Guitarworks, is that they will actually test the pots and if you want a 500k pot, then you will get a 500k pot. Normally, they would be anywhere from 350k to 450k.
Another nice thing about vintage wire, cloth type at least, is you don't have to strip any wire, just slide the cloth back.
It does look cool too. Some folks care about how their cavities look. Some don't. Who am I to judge? That would make me like most of the posters in this thread.