My new cruiser is equipped with the new low radar arch. All the wiring runs through the arch down into the cabin, but it seems to be wide open to the weather. With the rainy season approaching, I'm concerned that water can easily find it's way into the cabin through the arch. Normally, grommets are used to seal these openings for wires, but there is one that is oval shaped and fairly large, that I don't think I'm going to be able to find a grommet for. Any suggestions on how to seal such a large opening?