Long Iron Peak Height - Clubhead vs Shaft

[MofoJones]

What's the most important factor in producing height in long irons?
Ball Speed? The technology in the clubhead itself - Ie. Club head center of gravity? The shaft profile you choose - different kick points and tips? AMT(ascending Mass Technology) in your shafts?
What is it?

I have always struggled in getting height in my mid-long irons. It really led me to struggle in my par 5 scoring when I am sitting pretty around 200 yards out from the green after my drive. I am a fairly high speed player (Routinely swinging it around 115-120 mph with my driver and ~129mph ball speed with 7 iron at 35* loft) so it just doesn't make much sense to me why I hit my long irons low. I would obviously like to jump on a monitor when I am using a long iron to see the dynamics that are going on, but there's just none available where I am situated. I do feel like I swing my irons on the slow side in comparison to my driver. 

As we know there can be added technology in the iron faces to produce more ball speed which is an important factor in peak height. There is also CG positioning in the face - the lower the center of gravity/mass the higher the club should launch and spin. For both of these reasons there is a strong following with amateurs and professionals to make a combo iron set. Get some added technology in those long irons to help you hit them higher and land like a butterfly with a sore leg. 
There is also the shaft profiles in itself that can be designed to help you with peak height especially in those long irons. These shafts have the same weight throughout the set, but they change their profiles according to the clubs; Short and Long irons. The more lofted irons will have a shaft profile to help you flight the shots down and the long irons with a shaft profile to help with increasing the peak height.
These shafts use a progressive kick point throughout the set make up - so the long irons will have a lower kick point/ softer tip.
An example of a shaft with this technology in them would be the KBS Tour FLT.


A Personal experience: 
I was wondering if anyone has actually compared AMT (ascending Mass Technology) shafts to their same weight counter parts via launch monitor? Disappointingly I couldn't find anything on youtube. Or compared the flighted models of shafts vs non-flighted in those long irons via launch monitor?
I have tried a friends Titleist T100 in the AMT White S400 and I was hitting his four iron in a much higher window than I was used to seeing. However I don't think it was a CAUSATION of the shaft. I play Project X 6.5 in some Mizuno MP-58 blades, so I have a few things working against me to get that ball in the air. While his 4i was a Titleist T100 that is supposed to have a little bit of added technology to help you in the long irons AND obviously the Dynamic Gold AMT White shafts. I would say there was a 20-30 feet difference in peak height. I instantly thought of all the par 5's I could crush hitting a nice high and soft mid to long iron into. Especially if the green is a forced carry with bunkers or water. 

Does anybody else have any experiences with increasing their long iron peak height they wanted to share?