The thing about researching something like this on the forums is that you get a lot of folks that have never finished an airplane who have lots of time to postulate on forums....
More than 10,000 RV’s are flying, and I would wager that the majority of them are using the aluminum rivets that Van’s specified on the plans. And I know of no bad incidents that have occurred because of it - never heard of a single one (and I have a pretty broad information gathering system in experimental aviation).
Build it how you’re comfortable with, of course - but be careful about which rabbit holes you go down - too many of them connect to a labyrinth from which you’ll never escape....
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)