I agree get in contact with Mike about the blades. Myself I keep several different sizes on hand in a couple brands, olsen and flying dutchman. I use the FD blades more. I used to use spirals , but now just can't get the hang of them. I can get tighter corners with a flat blade. Mike has great service and can point you in the right direction about which blade is best for what you are cutting.
I order my blades(both brands) from the www.woodenteddybear.com just for the fact that when I order blades I am usually ordering patterns and other supplies I use.
As far as finish never used lemon oil, but like Chris I use spray poly. Or spay acrylic both with a satin finish. I don't lke thing extremely shiny.
Good luck with the new saw, and hope to see some of your projects.