First off, the first part of your post doesn't really ask a question, its a statement. Your getting one made, excellent. Pleased for you. That "guy" at Sims is probably Martin the boss and one of the nicest and most helpful people in the business.
You will get a top notch plate from him, rest assured.
Re the second part of your post, is your bass making excessive noise then? If it is, then I am surprised on a MIA P bass. If not, dont worry about screening etc.