My TA 152 will have a 118" span. It is a ton of work, but a dream build of mine really.
To be honest, I did not bother fixing any dents on my top wing. They were very minor, and would not have effected the alignment of my wing. Maybe the best thing to do would be to place some glass cloth over that area. Be sure to grease the blind nuts so they will still function and not strip or spin off.