I used this for my 2009 rvision trail cruiser c-17.Hope this helps ??https://www.amazon.ca/AP-Products-018-318-Rubber-D-Seal/dp/B007EXP9KC/ref=mp_s_a_1_1?dchild=1&keywords=Products+018-318+Black+3%2F4%22+x+1%2F2%22+Rubber+D-Seal+with+Tape&qid=1633307...
Excellent mod, archie18! I've been trying to decide what to do with that same space in my little 17 footer, and you gave me the perfect idea. Thanks! How'd you get it to stay? Anchors and glue?