[TowerTalk] Does it matter how long it is?

[Gene WØQFC]

I have been having a discussion with a local ham friend about how long is my mast.
When I put up my newly refurbished Aluma 40' crank-up tower, I only put a 2'  dia, 2" od section of mast out of the top of the rotor (G800-SDX); The only reason I used the 2' section is because it was what I had on hand and I was concerned about too much mast sticking out of the top of the rotor. (The rotor is top mounted on the tower).
My friend says that I should use at least a 5' section of mast because it will make a difference with performance of the antenna (TA-33SR WARC).
I told him I don't think that an extra 3' in elevation would make a bit of difference. 
As it stands now, with the tower cranked up all the way, the antenna is at about 42' above ground. I am sitting at aprox 170' above sea level at my location.
Soooooo, what do youse guys have to say????
Tnx 73

Gene, WØQFC