This is just MY OPINION; placing the control of the finished product into the hands of a generally untrained client is going to lead to MAJOR issues down the road.
IF you give them a "variety" of choices on exposure, and saturation, you WILL end up with problems.
It should be YOUR decision on each job what will serve the clients best interest, NOT the other way around.
And lastly, IF you have a client who "thinks" they should be making decisions as to what "Saturation, and Exposures" will best represent their final product, {this is what I WOULD do} send them packing. Anyone THAT critical of the outcome of a finished product will NEVER make you any profit. ONLY HEADACHES!