Share 'Adding Own Ingredients.'

Hi,I naturally have thought of adding my own ingredients to a 99% couverture chocolate I can get hold of. Is this an easy thing to do i.e can I just simply add my own milk powder and cocoa butter to a melted chocolate? can I add things like a liquor, Cognac or even fruit juice, for example juiced straberries ect?PS. Can I use liquid milk instead of powdered form? I'm from England and there's a ch…