More info on "Bach Three-Part Sinfonias, Volume 1"

Included are the first 8 of the 15 three-part sinfonias.
None are in their original keys; keys were picked to
fit the range of the instruments.  As a result, the trumpet
almost never goes above the staff.  The horn rarely goes
above written G.  The trombone part is within the
tenor trombone register and will sound great on tenor
trombone.  It is of course biased toward the lower
register, being the lowest counterpoint line.  As such,
it would sound great on bass trombone as well.
The substitute trombone part (substitute for horn)
never goes above C, and or course is much lower than
that for the majority.