Thanks guys. I still think some hand positions look very close to horizontal but as I can imagine that it may be uncomfortable to handle a bow like this, I'll have to put it all down to an optical illusion.
And here's me thinking I'd discovered the next level in bow gripping development.
There was a movement in the 70's to what you describe, an almost horizontal grip. So nothing new in that idea. One person I knew actually designed a riser with the grip designed to accommodate the style. 90% or more of that riser was then adopted by a famous(ish) bowyer who then produced one of the best selling bows of the period for his employer, from my friend's design. My friend was so appreciative of the professional bowyers compliments, he gave him a casting from the original wooden sand box mold to work with. And the ******* bow was born shortly after.
That would be when the Friskney bowmen indoors series was at the Golden sands ballroom complex in Mablethorpe, with around 40 bosses or more in the line to accomodate the entries. Us field archer compounders were always banished to targets 40 plus. Only 3 or 4 of us were shooting wheelies at that time, GNAS did not recognise wheelies then, 1974/5 ish.
Keeping the bow hand horizontal was very draining, as it required a lot of physical effort, and it was very easy for the hand to go over horizontal, and be pointing slightly down. The theory was that it gave minimal riser contact and reduced torque as well as reducing heeling/palming of the riser too. Theory good, in practise, not so good. Tried, tested, no real benefit, dumped and we moved on. Like so many seemingly good theories & ideas of old.