I'm going to drill for a White Lightnin touch hole liner in a 1" barrel for my flintlock. My touch hole will be over a 1/4" forward of the breach plug.

Is that too far forward of the breech plug?
Thanks

Finally, something I actually know something about; I have installed lots of them. The answer to your question is, no.
Normally you wouldn't put your lock so far forward.
Anyway, no problem on 1/4 inch; as long as it reaches the powder it will work and any powder charge you use in it will be much longer than that.