Use TWO keel strips! DO NOT glue them on! Use doublesided tape instead. These strips will have to be taken apart again when the finished piece is to come off of the frame. Taking the strips apart helps to remove the various strips of tape (see image later on here). You can permanently glue the keel strips to the end strip if you want, because doublesided tape is difficult to remove there.

From now on, all strips are being permanently glued together.