When it comes to making HST's a lot of people have a hard time. They never come out right. I've had this problem too and stayed away from patterns that had HST's.
Until...I came across a method called the "Cut-Down Method" created by Rhonda Woodsmall. www.bitsnpiecesworkshop.com
With this technique your HST's will come out perfect every time. No more wonky squares. Your blocks will be so perfect that you won't have to square up the HST's.
I no longer shy away from any pattern that has a HST. If you don't believe me, just try it for yourself. Go to www.bitnpiecesworkshop.com
Wow this sounds like a commercial...lol.