I only do SITD and always start in the middle, do upto 3 vertical lines down to one side then go to the the other side and to three, then back to the right, back to the left, etc. Flip the quilt, start in the middle, repeat process. Then go back and fill in other sections once the main quilt is stablized, this seems to create the least amount of chance of puckering along the runs.

I use a 3.5 stitch length with a walking foot, my machine does have automatic thickness adjustment though as well.