Hey...has anyone installed D-Ring tie down anchors on the shelves of the passthrough in a Windsport 29m? My only concern is what is under the shelf? If there is a tank or electrical. I plan to use shorter screws, but anyone have any suggestions? I want to be able to tie down the narrow items we want to carry on the two pass thru shelves. Obviously we can't carry much as the passthroughs are only 6 inches tall.