Wow Alan. Those look like they could work really well. You may have to cut off the standoffs with a coping saw to get a clean and even fit around the perimeter of the raised part. Or maybe, if the weather stripping is sufficiently tall, you can just wrap it outside of the raised portion.
Let’s see a photo of that when you get done.
Using the medical grade tubing I discovered last week and your improved way to seal the outlet could really help improve sound quality and playability.