The only real way to know what is going on is to measure everything out. Block up the tail while on a flat table and level out one wing tip. Then measure out the remaining 3. Good news is that with iron on coverings you can twist and re tighten to fix. I can't tell you how many times I had introduced a twist into a wing while covering. Once you have the wings straight, make adjustments to the struts. Once everything is set correctly the wings and struts become a box structure that will keep the "set"

You may also want to consider putting 2 or 3 degrees of right thrust into it as well.