If you keep the toffee in an air tight container it should be fine.

White chocolate isn't too difficult it's just softer and can split because it's more delicate. But I don't imagine it would be a lot harder.

You'll find most White Chocolate recipes contain more white chocolate than milk chocolate recipes. So make sure you don't substitute a milk recipe for white, unless you use more white chocolate. For decorating I normally do 3 parts white chocolate to 1 part cream.

AND A BIG FAT YUM!