Thanks @JohanH,
My design is very similar in principle to the Scullcom/Barbouri design. There's a lot to be said for piecing a lot of application notes together, which is how I started and I see how Scullcom has implemented some aspects. According to the simulations, i've been able to tune the theoretical accuracy to 0.015%, but realities of construction, temperatures will certainly mess that up.
I'm struggling to find a panel meter of low power. I could use the PM328 LCD panel meter which is only 0.5mA, but requires 7-12vdc and isn't isolated. Conversely, the same panel meter used by Scullcom is slightly less accurate and draws closer to 50mA, but is available in an isolated 5V version and is much cheaper.
One of my aims was to make the meter very compact and low power, so i'll be balancing that with the above panel meter selection. I could make my own, but...