Hello Cliffy,
A seller whose eBay name is interslice sells excellent custom light-seal kits at a very fair price, under $10 US. His actual name is Jon Goodman. I recommend him highly. His kits come with excellent instructions and he is open to questions by email. Here's a link to his current listings:
http://shop.ebay.ca/interslice/m.htm..._sop=12&_rdc=1