I know it's a bit late for this thread, for which my apologies, but...
I had a test ride on a 53 M Agattu at the weekend, and it was WAY too big for me. I'm 5'10'', inside leg 29", and it was only too big because of my disability - one leg. To start off on a bike, I have to mount cowboy fashion (swing leg over saddle), sit astride the saddle, one foot just touching the ground, plastic foot just missing it, and push off with plastic foot.
This wasn't possible on the Kalkhoff, even with the saddle as low as it could go. I managed to ride it, but I'm still feeling it, in my extremities.
Moral: most DEFINITELY go and sit on one before you order. They are big bikes; the bottom bracket is inches further from the road than normal, and consequently the saddle it that much higher than normal.
Allen.