DJC, i'm afraid that Billnpatti is correct - you'll need a micrometer to measure the patch thickness, and then you'll need to figure out where they came from, if that company is still in business, if the thickness changes from lot to lot, if they always use the same lube from batch to batch ...
aaaaargh!!
here's what I would do: grab your credit card and go to this web site:
http://www.blackpowderrifleaccuracy.com/
then plonk down the twenty bucks (I think it's still twenty bucks - a very good bargain, especially if you consider what even a half hour of coaching would cost).
this is Dutch Schoultz' system, and it really does work.
once you get it working, you will be able to go to the drygoods store and get a veritable infinity of patching material for a very low price, and you will be in complete control of the whole patch process from beginning to end, thus ensuring that your results will be repeatable and reliable (that's know as accurate out here in the great frozen north)
you'll still need to get a micrometer, but that's a tool worth having anyway ... I got a cheapie from Harbor Freight
http://www.harborfreight.com/0-to-1-inch-range-digital-micrometer-895.html
(this looks a lot like the one I have ... another twenty bucks ... well what the heck, you didn't want to squander your money on useless junk like groceries, didja??