Francois de Larrard wrote:
As a matter of fact, there's no indication for the first movement, but there are for the two following ones, as in my edition.
Yes you're right. In fact he wrote tempo indications for all trio sonata movements except the very first, so we should do it the same if only to be politically correct

Francois de Larrard wrote:
You mean 'this may happen unless they are really extremely good' ?
Yes, that is what I meant. I collaborate(d)
with different string players and it's very hard for them to be always exactly in tune. We should not bitch at them too much, they are doing their best
