Getting the buttery flavor that vendors use diketones to achieve might be complicated with FA.
I hope someone else will jump in and help you out with more specific advice, but my guess would be it might involve cookie, caramel, maple, vanilla--with maybe a little extra acetyl pyrazine to bring out that fried-in-a-skillet kind of thing.
There is a juice I love but it has a french toast flavor. Can a french toast flavor be created using only FA flavorings?