Best Intermediate Euphonium: Besson 1065 ? Yamaha 321 ? or other?
My own experience with the Yammie 321 goes back 30 years, so my opinion is likely confined to the Horn Graveyard.
That said, I never cared for the Yamaha. For me, it was a delicate horn that didn't withstand normal Army band abuse.
And speaking of abuse, considering your son is still in high school and likely will play in college, there is that aspect to consider - you'll want a durable horn if you're going to plunk down the money.
If money is no object, that's another situation altogether. I'd get him a good intermediate level horn now (plenty of others on the forum have much more recent info than I do) and a pro horn later on.
And yeah, the 3+1 arrangement now is the way to go.
Just my two zlotys.....
U.S. Army, Retired (built mid-1950s)
Adams E2 Euph (built 2017)
Boosey & Co. Imperial Euph (built 1941)
Edwards B454 Bass Trombone (built 2012)
Boosey & Hawkes Imperial Eb tuba (built 1958)
Kanstul 33-T lBBb tuba (built 2010)