Hmm, I did think I'd just be able to use a small fuse, but I see now that it may not be as simple as that.
I think what I'll do is drill the hole at just over 1mm, and try the brush bristle technique.
If that doesn't work, I'll try the countersink and torch method, and if that doesn't work, I'll enlarge the touch hole and try finer powder.
I'm reluctant to drill the hole at 1/16" (1.6mm) without trying a smaller one first, because you can't drill a hole smaller
I wonder if some type of electronic ignition would work?
I could probably rig up something with a nichrome wire element, or maybe even the piezoelectric sparker from a lighter (will this ignite black powder?)
Would electronic ignition be legal, or is it too 'modern' to comply with the law?