If you are doing pool pcb manufacture - think about getting your design rules as a template in KiCAD (you could talk to KiCAD services corporation about how to do that) or Altium. This would help people designing to avoid getting to a finished pcb then discovering that you have a rule about no route through pads or whatever.

> For 5 units of 2 or 4 layer turnkey assembled boards, so long as you fit in the Grid Proto spec it's a little bit more expensive (not 10x, more like 1.3x)

Does that include the cost of parts? One of the issues I had with sourcing prototype PCBA's in the US is parts are much more expensive (not 10x, but also not 1.3x).