I used a water based stain from Wilkinsons (medium oak).
I actually dipped them as, at the time, my right arm was in a cast following an
op on a tendon in my hand/wrist.
Therefore it can out a bit blobby in some parts but here's the results:
The picture isn't the greatest but I was very happy with the results.
Re your question over what colour to dip, trial & error is your friend. If you're like me you'll have plenty of spare minis floating around that are of a similar nature to your guard.
May I also recommend that you look at Halford's yellow ochre primer - this might help you save time if you use the yellow as a base coat as well as a primer coat. I can't find Tallarn Yellow on the
GW website so can't tell how dark it is.