Max. recommended head speed for 690s?

[DAldridge]

I'm wondering what the maximum recommended head speed is on 690s (Rail blades, of course)?  Can it handle extreme 3D and/or speed runs at 2300 and 15deg. pitch, for example?  (Not that I'm that capable, but I'm wondering what the machine limits are).  Or do I need to keep things at the typical 2150 or below?

[steffgiguere]

Matt already tried his E7 with 710mm blades running at 2500 rpm, therefore this heli will handle 2300 and 15 deg pitch. But flying it at 2100 is great.

[Matt Botos]

I prefer the 2200-2250 myself.
The tail performs much better at this head speed.
It all depends on how you would like to fly.

Matt