The best advice I got during the build was: if you want to fly your plane a lot when you finish it, look at people who are flying theirs a lot and do what they did.
The implication is that you avoid as many "modifications" as possible, recognizing that there are some great ones for the RV-10 that are well worth doing. But folks who get carried away with add ons run up their cost, their time to build, and frustration level.
Burt Rutan is famous for saying, "once you have all the essentials on your plane, if you want to add something, throw it up in the air. If it doesn't come down, you can add it."
The other thing I would tell you is, if you don't have any experience building then get some training. The more the better. It will save you years and many $$$ and greatly improve your chances of being a finisher instead of a seller.
=VAF= 2018 dues paid