I can't get them to stick to the Shellac residue so I use the normal nail foil glue, it only takes a minute longer.
The base is the Shellac Chrome so that any missed spots don't show and the Shellac Top and Base coats as normal.
Decals purchased from: http://www.etsy.com/listing/93386036/love-hate-block-style-nail-decals-black
Similar foil available from: http://stores.ebay.com.au/shardeedesigns