Dryness comes from overcooking, not higher cooktemps. (I cook ribs 325-350.) But higher temps makes for a rather narrow 'done window', the spot where tender in first achieved to the point where overcooking starts. Better to learn the ropes first, get comfortable with your cooker and your cooking, then modify if you choose.
The info at the above links is a good place to start. Post to the Barbecuing or New WSM Owners sections if you have questions about anything before you cook, questions during cooking, or questions after cooking or about your results. Have fun with it.