17 was one of the first built with dual propane
, the storage box, and an electric tongue jack. The Camco propane cover was so tight that it was difficult to open & close the storage box.
Since I've done quite a bit of Vacuum forming prior to retiring, I used the same technique to "flatten" the back side of the cover. After removing the cover, I used both a 1500 watt electric heater (inside) and a heat gun outside to soften the plastic, then pressed it against a flat surface. There was plenty of room inside the cover to still fit the tanks after flattening about 3/4" at the top rear.
Don't know if this would solve your problem, but it worked for me...