Thanks matthewdelacruz (big fan of your costume builds btw).
The string I'm planning on using is standard ball-of-string type string (I'm not 100% sure on the thickness -- 3mm or something like that)
The string would probably just be glued onto the costume.
I'll take a look at the Tulips puffy paint, and hopefully I'll have some progress photos of the costume soon.
Kind regards, The14thDr