I've been playing with this for a few days now, I checked the timing at 2000 rpm and as hoped it changed both with and without the vacuum and by different amounts.
I've had it set at 15 degrees for a few days and it's running better than it was however twice now when I was turning the engine off it ran on for a second or so before cutting out.
Just out of curiosity I turned the distributor to where the idle peaked and ran smoothest and measured the advance by turning the dial on my light until I got Tdc showing. It was at 35 degrees, is this normal at all?