I'd recommend the Chestnut spirit stains, they do a "rainbow" colours trial pack with quite a few colours (half or more of which you probably don't want, although might make for interesting mixing experiments). I found them easy to apply, and will still allow the figure (grain) of the wood to show through, although this does depend to some extent on the texture of the wood. So ash, for example, might show more contrast than sycamore, probably because of it's coarser (?) grain structure. Raising the grain before or after application of the stain would probably make a difference (moisten surface with water and rub back with sandpaper when dry). They are soluble in meths, but I found that they seemed to bleed a bit when I applied an oil finish over the top (not an issue if you just have a single colour). It is absolutely vital to have a good surface finish when you stain as any torn grain will stain much darker and be rather more obvious then if left unstained. Do not underestimate the last point!
I hope this helps.
Cheers,
Dod
