200 acre lake is a large piece of water to try to control. If their calling and decoy placement is up to par and they have not overshot the place, they should be able to so if they are worth their salt as a "Guide". I have hunted places that had "Guides" and they could not call to save their a*&!!! It was somebodies kid needing a job and could make some noise on a call that the owner could not tell the difference between a duck call or a kazoo. If the "Guides" know what they are doing, they should be able to adjust on the fly and make it happen. My .02 cents.