@JustinTime you are right. The first thing that striked in my was Dust Collector attachment while I was cutting my first test cut. Although I don't have a professional dust collector. So I am planing for cyclone bucket attachment before vacuum cleaner. After first cut I also realise that Y rails must be placed on sides instead of bottom.
I think you might find a small pair of sprung loaded roller blinds will do nicely to protect your runners. Put one in front, and one at the rear of your bed, and they will expand and contract as the bed moves front to back. Gray