Welcome @a_pinch_of. Glad you have moved from stalking to posting!
I think I would initially still wrap my bars in the food grade cello, then wrap that in the greaseproof paper. That way the shelf life would not change from what you get now. I'd explain to her that because you are using freeze dried fruits that you need to successfully exclude as much air as possible and the cello will help with that.
In the US - what is known as greaseproof paper in the UK is usually called glassine paper. Here is one vendor online who has black sheets of glassine.
Where are you located? Are you aware there is one spot left in the eG Chocolate and Confection Workshop in May in Vegas?
