It's disheartening to put in so much work on a Lone Star and then have it turn out this way. All the suggestions I've read are good .... it's those bias edges that give you trouble.
Another thing you can do: Steam PRESS, don't slide your iron. A lot of that (but probably not all) can be gotten rid of by shrinking. Don't give up after one time; press, let it dry, and press again and again.
Good luck!