Ed, just use motor brushes.
You can find them via a ton of sources, even eBay.
Get the ones that have a wire already embedded in them.
Something like this for example.
http://www.ebay.com/itm/Electric-Mo...520?pt=LH_DefaultDomain_0&hash=item20e9a61288
They work great, I have made several, for myself, and friends.
I used pretty small brushes, and swipe, to get a mark that is superior to most others.
Big blocks that cover the whole stencil are sketchy, unreliable, and unnecessary.
FWIW, current draw is going to be determined by the opening in the stencil, and how much of your pad is in contact with it at an given time.
I find "swiping" with the leading edge of a pad to be the most reliable, consistent method for marking.
You have absolute control this way, and every bit of your mark gets the same amount of exposure with this method.
Not so when a big old pad is covering the whole stencil.
Uneven pressure, outgassing, etc... means you can get an uneven mark.
Check it out.
[video=youtube;z3i3h4v27As]https://www.youtube.com/watch?v=z3i3h4v27As[/video]
Now, I just use my laser...