For the outside I didnt have too much to fill, thanks to the good advice of using tons of hysol in there. I just tamiya putty for now.
Attached are some pics of the result. I sanded out the 90 degree lip on the inside of the fuse where the cowls mate up. Am I supposed to sand anything else? I got the bottom joint sanded well but not sure how much it needs to be sanded down. I plan to put some thick glass across these joins as far forward into the intake cows as I can get.