[turf3]

Depends on the instrument.

The ideal vent would be like the other two register vents, i.e., a small hole on a tube extending into the bore. Because, instead, you're using a regular tone hole, the whole thing becomes a compromise. Right off the bat, it plays a half step high on high F (the 3rd order of the A being fingered is E, not F) and a whole step high on high E (The 3rd order of the G being fingered is D, not E).

If it raises up too much, it MAY be more difficult to access certain altissimo notes that use that key; and they MAY run sharp. IF it doesn't raise up enough, some of those notes MAY run flat.

I have saxophones that like the pad opened about the same as with the palm key, and I have other saxophones that like it just cracked open. It's an easy thing to adjust and try, and the adjustements are easily and fully reversible. For that matter, for trial purposes you can stick a piece of heavy card under the foot of the F key and open it with your LH ring finger while fingering the different other keys, and see if you can discern any difference in response. Typically this is one of the very last things I adjust when I'm getting a horn ready to play (because I am the only one playing them, I simply set them up to my preferences).

 

[turf3]

Altissimo G natural is notoriously difficult on King tenors, and for years I disliked that note on my King. I knew about he practice of opening the front high F just a crack to better enable altissimo G, but I avoided that adjustment because I didn't like the severe lost motion it introduced to the mechanism. After reading this thread, I tried the suggestion to play altissimo G with a business card under the high F key, plus the left hand B key. I got a great altissimo G. I feel a little foolish that I had not tried this trick before, but I immediately lowered the alternate high F key height to about 1 mm. Thanks, Steve P.

I once had a tenor (Dolnet) where the mechanical advantage of this linkage was adjustable, so you could have the pad crack open just a bit with the front key; open fully with the palm touch; and no/minimal lost motion. Selmers also have this; it might be possible to modify a King.