After three attempts managed at least a wearable fingering weight glove. It is functional, durable and really warm.

What I learnt from the exercise:

Don’t over engineer, lessen the number of decreases behind the thumb and space them out more.
Back loop sc probably gives the stretchiest stitch and it looks good from both sides.
The purl bump cast on with a row of slip stitch worked on a size larger hook is probably preferable to the stretchier chainless cast on.
Like amigurumi, go for a smaller rather than larger hook for the yarn.
The invisible decrease is the better option when decreasing than a regular sc decrease.
Create the smallest finger bridges you can get away with and do not allow extras for corners or decreases in the finger spaces.
The round join works very well palm side of the hand lining up with the little/ring finger space.

Good enough to try again at least. Will just relax the fit a little more so there is a chance they could fit more people than just me. Can’t wait to try finer yarn and introduce colour. Two colours at this weight probably not a good idea except perhaps for just the cuff section.