I can't be of a lot of help but can offer some tidbits. I handlay but spike into wood ties. However, I do have to use pcb material for the throwbar. I don't remember the thickness of the pcb sheet I bought, I bought mine at Radio Shack, I brought a wood tie with me and bought pcb material jut a tad less thick so it could moce freely. I have cut ties from the sheet with a regular Xacto saw, but it's not much fun. I'm lucky to have a friend with a small power saw and he cut it into strips for me, so then I only had to cut them to length, much easier. You only need copper clad on one side, bur double sided won't hurt anything.
Since you are soldering rail to pcb ties, the thickness should equal the ties on the rest of your track. You can buy pcb ties from several sources but od course it will cost more than making your own. I only had to worry about throwbars, if I were using instead of wood I would definately want a small power table saw.