Got it on the pump style --- was told a long time ago that pump must be designed for belt/chain drive and direct would have to have outboard bearing mount. One of my pumps is belt drive off of an old combine and the other had been direct front crank mount with thick flex plate to cushion it. This one would need the outboard bearing. I have one that according to specs. could run belt/chain/or direct. Just have to watch which one I use.
On the res. mount, I always put them above the pump a bit so fluid is gravity fed down to the pumps to keep air from being sucked in.
These pumps I have do have rotational arrows on them. The specs. on one is either way---just gotta hook the hoses to the right port!
Just never mounted one on end before. could run with twist belt and put pump horizontal but dont really want too.---prefer straight runs on the v-belts IF possible.

"A machine you build yourself is a vote for a different way of life. There are things you have to earn with your hands."