[High-Speed-CW] Nominal max speed with straight key? with coutie key? iambic keyer?

[Paul F. Sehorne]

What would you say is the nominal max speed with straight key? with 
coutie key?  My practice with a coutie key indicates max speed might be 
in the 25-28 wpm.  I don't have a straight key; so I'm guessing, but I 
would guess 15-18 with a straight key.  I also arriving at the 
conclusion that to max speed with an iambic keyer and dual paddle is 
only a few wpm more than with a coutie - perhaps 30-35 wpm. 

 From those of you who have actual experience on the air with these, 
what has been your max speed, with the system(s) with which you have 
experience, before everything begins to fall apart?

If I'm correct, then the high-speed c.w. above about 35ish must be being 
sent with a keyboard or similar device.  Any first-hand info on this?

In every case above I'm interested in what can reasonably be expected, 
not the exceptional individual that whizzes along at twice the speed of 
a normal human all the while walking and chewing gum.  These stories 
would also be interested, but it would be nice if they are identified as 
the exception.

Thanks,
Paul, WI5F