More or less what Droogs said. The traditional grain direction for totes (& saw handles) was chosen as the least bad way to cater for the compromises needed to use wood for the job. I've repaired & replaced dozens of plane totes in my time & often wondered if I could orient them better, but short of finding a piece of wood that has some very peculiar grain directions, I long since decided we are stuck with the 'traditional' orientation as the least worst way.
The weak point, and the site of the vast majority of fractures I've seen, is across the 'short grain' of the grip. This is normally countered by being held in compression by the stud, but if the stud becomes loose (or the plane dropped!) they can & will break, typically at the ankle or just above it, as happened to this old rosewood tote:
It also needed a horn graft, as you can see. Broken horns are by far the most common lesion I've encountered on plane totes (& saw handles).
By orienting the grain running in the direction you've chosen, I think you are swapping one set of risks for a higher set, as already pointed out. If the stud gets loose (and it frequently does) a break across the "foot" is a near certainty. The entire horn is also going to be a very flimsy affair and you'll need to be very careful with that.
Accidents do happen, unfortunately. I've knocked planes off the bench at least twice in the 60 odd years I've been mucking about with them. One landed on the corner of its toe & all it took was a little bit of file work to clean up the burr on the metal. The other, my very favouritest 5 1/2 I got from my dad landed smack on the tote & broke the tip off the horn (but the rest of the tote remained intact):
As you can see, with the curve of the horn, you end up with some short-grain towards the tip, which is why so many old totes are found broken off near the tip anyway. Orienting the grain the way you want to is going to make this vulnerability even worse.
However, I believe in the old adage of "suck it & see" . Make a new tote the way you think is better & who knows? It may last for the rest of your lifetime (if you give up this dropping habit
), but there's a fair chance you'll discover why they've been doing it the "wrong" way for the last few centuries. A lesson learnt through experience is far more valuable & memorable than simply being told.....
Cheers,
Ian