Can somebody explain to me the secret of different diameter high f-tone holes

Hi,
a friend of mine, who owns a music store, has saxes made in Taiwan and sells them under his label.
After some time when you could not really play them for intonation reasons he, by the help of some jazz greats in my country, had some really great playing horns, like the Mark VI, with small diameter f tone holes.
They had just one fault: The mechanic was bad, and after a short time of playing them, they made really bad noise.
So he switched the manufacturer of the body to the works who also makes the Mauriats.
Now the keys were great, but they did not produce extra corpusses for my friend, (except he would have bought thousands of them), just the standard ones with large diameter f tone-holes.
Trying different horns from both series I can only say that they play totally different, and the ones with the large holes are very out of tune on high e played with the front key.
I am used to the large f tone hole, because I play a Selmer Ref 54, which has the same "problem".
The musicians who help my friend (and almost all of my companions at musical work) who play vintage instruments say that "the overtones are not correct" with the large diameter horns.
So what really are the advantages of the small diameter, the disadvantages?
Why is everybody producing horns with large diameter?
Yesterday I visited the store, and tried a "Mauriat".
While I do not have any troubles to get a correct intonation, a good friend and fine jazz player, who coincidentally tried some necks for his Mark VI could not really play the horn. He got terribly flat from high c up.
So, can somebody give me some information?
Thanks,
Mugger