Sewing Stretchy fabrics by hand...an experiment

As a committed hand sewer I have always avoided knits as assumed you need a surger or at least a sewing machine with a special foot. Anytime I've asked about sewing anything with stretch by hand I could feel the looks of surprise and alarm.
Is it so shocking that no one has ever sewn stretch knits by hand? lol! It can't be any different than sewing wovens on the bias can it?

And as if to prove me wrong I find this little gem of advice. And this one.

Herringbone stitch is one of my fave decorative stitches. So wanted to see if it truly worked. I had some stretchy material that I couldn't resist buying in my stash (so soft and drapey) so I cut off a strip and did an experiment. Now if I remember science at school you have to write about it.

Resources:

Stretch jersey fabric
1 sewing needle (just the one that came with my sewing kit)
1 spool of normal thread
Pins

What I aim to find out:

How different stitches affect the stability of the seam, allow for stretch and look best. In other words what is the best hand stitch for sewing stretch fabric.

What I did:

I cut out 6 strips of the material on the same grainline.
Pinned the pairs together.
Sewed each pair with a different stitch
Observed how the seam looked on the side that would be visible on garment just as is and under stress.

Results

Stitch 1

Stitch 2

Stitch 3 (control)

Conclusion:
That both under stress and 'relaxed' the running stitch looks the best.

If anyone has any other hand stitch suggestions for stretch materials I'd love to hear from you as I will keep experimenting.