Hand built wheel question please.

Im a mountainbiker of 20 odd years and im building my first ever road bike through this winter.

Im looking for advice on spoke count for my wheels.I have decided on Chris King R45 hubs but currently undecided on rims (happy to take advice here too).

Obviously looking for a stiff and reasonably light build.Im wondering if i could get away with 28 spokes or to stick with 32.I weigh 13.5 stone.

Many thanks for any replies.