hey Maddog, welcome to the forum and your plans sound great. Post some pics of the body when it arrives. Grain filling may only level it off than make visual improvements if you use black stump. I still think its worth grain filling so go for a dark timbermate or a light timbermate will highlight the grain more.
I built a ash explorer but didn't grain fill but was happy how it looked. Without the grain filling I got the grain lines showing through in a lighter colour