I also believe tilt up hoods benefit from horizontal exhaust.
No doubt. Horizontal exhausts pretty much leave the hood untouched.
My old Kubota had vertical exhaust that came off the exhaust manifold, passed through the side of the engine housing, and curved upward. There was a little panel in the side of the engine housing between the exhaust and its top edge, held on with two bolts, to allow removing that side of the engine housing. It worked, but obviously was a little more trouble, both to manufacture and to service the side of the engine. On that machine, the hood was hinged at the front, and was above the engine without covering its sides; the sides of the housing covered the sides of the engine and were independently removable which I did from time to time.
The new tractor hood covers the sides of the engine as well as the top, and hinges just in front of the instrument panel. On this conversion, I cut off the exhaust pipe at a location where it's running straight downward, hidden by the hood. Since the flex tubing makes a U turn below the bottom edge of the hood, it doesn't interfere with the hood at all.
I also like that there's a trap there, like a sink trap. If somehow it did get several inches of rain, it would fill up this U turn for a long time, then the horizontal muffler under the hood, before it got into the engine. I always disliked the old Kubota exhaust design that would funnel rain water into the exhaust manifold eventually. I bought it used, and it always looked like it was rode hard and put away wet. The first time we started it in the dealer's back lot where it was stored, a bit of water flew out of the exhaust.