It's a good design. For what it's worth and I'm sure someone will disagree with me, I wait to stitch the trigger guard side. I stitch my slide side then I put the gun in the holster. I press the holster a bit with my fingers to get the leather close to the bottom profile of the gun. I then trace the profile. Remove the gun. Over stitch the line. Punch my holes and stitch. I have gotten good results with this and am always able to get the trigger side stitch line really close. As said before when completed you want the holster to be tight. I almost want to think it should be a bit tough to draw. When the leather moistens and stretches it can get to be too lose and can become dangerous. But that's just my two cents. I'm new to the holster business but I have carried a gun for over ten years.
Also in respect to the strap for the thumbreak I initially had the mindset that the strap was there to hold the gun down and several of my straps were way too tight against the gun and would become distorted. The retention in the mold is what holds the gun in place. The strap is just extra insurance. A well molded holster should never even need a strap in my opinion. It's just the persons preference.