Climbing a learning curve certainly takes its time

I've been learning more about embroidering large items without creating puckers. It's certainly a challenge, but finally I've made visible progress. I must have stitched more than 15 different samples so far. When this project is done, though, I'm taking a break from doing major projects for others, and just focusing on making good, simple, small quilt labels.

Goal: stitch out several 4 inch high letters, with pretty wide lines.
The fonts initially digitize as satin stitches, and this causes all kinds of puckers if the fabric is insufficiently stabilized, or if any of several other factors are off. Examples are  stitch density, stitch length, fabric quality and thread tension.
The first two pictures below are the successful one, showing a front view and a back view.
The photo at the bottom, the red thread, is an interim step, in which I experimented with several different stitch densities and lengths. This is just a few of the stitchouts I've made so far.

In general, I learned:

• For big dense projects, use iron-on stabilizer whenever possible
• 2 layers of stabilizer placed orthogonally give the best stability
• A relatively short fill stitch (3.5-4 mm) is far better than a wide satin stitch
• Even increasing the stitch spacing from .45 mm to .55 mm makes a visible difference
• Jennie Perkins' Tearaway Magic, an iron-on water soluble stabilizer, is NOT appropriate for this density and size
• With large lettering, add an edge underlay around the letter
• Stitch a basting frame as the first step
• Don't hoop too tightly, just flat and in the hoop is better than a tight hooping