Lavender and chocolate splits genetics question

[SourRoses]

Is there a way to breed lavender over buff to get a champagne or would they always default to Isabella? I mean if the lavender dilute gene can be put over a bird with a completely buff or red base and no black?

I'm not a genetics expert, but I believe that Isabel is made on different bases in different breeds. In some it's Wheaten, but in others it's Buff (if memory serves). So I think the end result of adding Lavender is similar.
I've read also that Buff is variable and can be hard to stabilize, especially in the presence of other genes.
But I wonder if an Isabel with some kind of red enhancement like Mahogany or something could take on more of a gold tint? I don't know if those genes are affected by Lavender or would make a leaky mess.