Dave,
i asked - do YOU have such ( 0.1uV) results?
In our practice we have 8 loadcells , each 30 thon - for truck
scale 60 thons or 80 thons. So (approved) scale's range is
(2(mv/v)*5(V))/4 = 2.5mV . For 3000 divsions - 0.8 microVolt/division. When scale is 2-interval type -> 0.4 microvolt. From this point i suppose 200..300nV is possible
with AD7730. So - comparing datasheets of AD7730 and CS55xx - i suppose You can ashieve 0.1 microV. Approval , offcource, is another deal.
About filtering - that Flitec was 805x. I prefer Texas MSP430.
At this time math is 40 bits floating point, but 24 bits maybe
will be enough.
regards,