Daimler made the first V-Twin in 1889 for boats. Indian set theirs at 42 degrees and fond it had better performance.
Harley has their V-Twin set to 45 degrees.
Geez, you’d think I wrote a paper on this for my MBA or something....oh wait, I did.
They found....they may have fond also, I just don’t have any facts to back up that statement.