Neat idea isn't it???
I did a few things differently.
First off I used regular clear straws so I have not worries about labeling. I can just see what I want.
Also. I do the fold and cover method on one end, and a heat seal on the other. (like you)
This link covers the http://www.instructables.com/id/Ultra-Li...le-the-Packets/
method to do this.

Best of luck
~Cole