The F in baroque fingering, all the holes are supposed to be closed except hole 5. If I open both hole 5 & 8, frankly
I can`t distiguish any difference between these two fingerings: only 5 open, and both 5, 8 open. Am I right?
Pls offer me some suggestion. Thnx.

On most recorders, with hole 8 open, the note is slightly sharp.

However this is not readily noticeable in fast passages, where you can get away with the easier fingering of having both holes open. :-)