Use Ultracote since you are not concerned about an exact match. Ultra cote goes on and shrinks at a noticeably lower temperature than Monokote.

Regular Ultracote and Monokote have heat activated glue on the back of the film. THE MONOKOTE TRIM PIECES (3" X 36" ) ARE SELF ADHESIVE.

Ultracote has a very easy to see and remove paper backing. When you trim the hole back, leave about 1/4" - 3/8" on each edge of the hole. You want to iron this down on the ribs and under the edge of the leading edge and trailing edge sheeting (a trim iron works very well for this) to insure the original covering doesn't slip on you.

After the edges of the hole are sealed, use some alcohol and clean the area abt least 1" back from the edges of the hole to get off any oils that may be on the covering.

Cut your patch so it is 1/2" - 3/4" larger than the hole. I suggest rounding the corners on the patch also to minimize/prevent the corners from lifting down the road.

Tack the 4 corners down, THEN seal the edges of the patch to the other covering.

Now you can shrink it down with the iron.