Hi,
Trying to follow the stitching video, using a single piece of leather. I stitch without casting and right side looks angled. I then cast and the left side looks angled, right side looks bad. Then switched back and, again, right side looks angled. Not sure how to get both sides to look nice. I tried left side forward up / right side right down. Nothing is working. Very frustrating.
Points are up and away.
Left needle goes through.
Right goes behind left needle.
Right needle goes through above left needles thread.
NO CAST
Pull needles through.
Right side is angled.

CAST
Pull needles through.
Left side is angled.
Right side looks horrible.

BACK TO NO CAST
Pull needles through.
Right side is angled again.

This is the back:

Updating my original post as instructed, used a thick piece of really low quality veg-tan. Much better results.
Tried for the first time, pricking with a stitching awl (see red stitch below), and I understand how it could open up more possibilities. Also stabbed my thumb pretty bad despite efforts not to do that! Usually use really thin pieces of chrome tan, so don't know if stitching awl is possible using thin chrome tan.