My first big mission is to plug that humbucker cavity. Pitbull was great and sent along some scrap basswood to help with that (they didn't have any alder).

I've read that lots of people use bondo to fill in any gaps and make it smooth but I'm worried that since the plug is a different wood than the body that over time you'll be able to see the outline. Am I being too paranoid about that or is there a better method that allows for more natural "breathing"?