How high?!?!?!

[Jinx]

I am setting up a drive thru coffee shop to open in May or June. I have studied countless floor plans and think that the plan I have designed will work, but.... what is the best height for the espresso machine be set at? I don''t want to stoop all day!! Help!

 

[CCafe]

The average person in the US is 5' 10". The average female is about 5' 4". I would probably set it a height comfortable for a person around 5' 8". I'm 6' 5" and don't mind machines set at my eye level but the average person always complains.