Like ihocky2 mentioned, I'd also say get some real pore filler or epoxy and play it safe. I've got a swamp ash body / walnut top project starting up and will be using Zpoxy finishing resin. I like the way if fills, sands, and looks for a natural or trans finish. Here is a good YouTube showing how to apply it with a squeegee
And here is some more usefull info from LMI http://www.lmii.com/CartTwo/thirdproducts....Header=Z%2Dpoxy