Hi Ste
The original spoke gauge used by Douglas, who delighted in being awkward, for the 1920s 2.3/4hp models, was 11 gauge. This gauge is no longer available, at least I have been unable to find any in the last 20 years or so. So you have the choice of using 12 gauge or 10 gauge. When I restored my CW I used 12 gauge which was quite adequate while it was being used as a solo machine. I have also used 12 gauge for my other 2.3/4 hp models except for the 1910 machine where 13 gauge was adequate. However, after fitting a sidecar I started getting the occasional broken spoke and eventually rebuilt all three wheels with 10 gauge spokes.
In respect of wheel build I have favoured nickel plated hub with black painted spokes, nickel plated brass nipples and black rim. The alternate nickel, black, nickel, black is most attractive and would I believe have been original in the mid twenties. If your front hub is not Douglas and it is not with 38 spokes, then I am unable to say whether the hub you have is capable of being drilled to take a larger spoke but normally with Douglas hubs (40 spokes per wheel for the mid twenties except CW model with 36 spokes per wheel) the spokes are the same front and rear in respect of gauge. Some of the earlier models had a different number of spokes between front and rear. Chris.