Hello, somewhat reputable place is
azarius, it's not too far from vondelpark. They stock sclerotia and I would suggest that you ask from the staff about the stones. Tell them what you are waiting from truffles and go from there. If you are completely new to psilocybins then my suggestion would be Atlantis or Mexicana A. It very much depends on what sorts of things you are waiting from the experience. Then again, do make sure that you take them in comfortable settings. AND NO, while it may be entertaining idea,
strolling around the RLD is not a good setting, think more of peace, nature, calm music and good people around.
For more info I suggest browsing through
erowid, since this is a coffeeshop forum.
Take care and have a pleasant trip.