First whoever made the bow comment, I mostly bowhunt I am sure I wound less, miss less, and look harder then most rifle hunters.
This is a tough question but, for sure on a bull like that, 2 hours is not enough IMO. A lot depends on weather, where you think you hit, blood, size of elk (this should not matter - but I feel you shuold give a longer to a 350 bull then a small cow).
On a bull like that, if you have any reason to suspect you did more then graze him, that day and all of the next day.
As for stopping hunting, I would live with not having too, but I would still hunt if legal. I have not lost and big game in a long time, and am very very careful - but if it happens on my once in a lifetime tag, after a couple days I am hunting again if legal. That is my feelings.
That said in my last 25 shots at big game, 20 went into lungs, one hit a shoulder (bow, small doe I did not realize she was slightly quartering towards me, this was about 8 years ago I love her), one hit a tree (I was trying to shoot through a 3-4" gap, missed by 1/4"), one my limb caught a pine I was tucked into and one my arrow caught a tiny twig immediatly after leaving my bow and cartwheeled. one I hit back on a walking bull, got excited. One went into the lungs and liver, not perfect but a good shot. One animal lost in 22, 3 misses (bow) all because of obstacles not shooting accuracy.
DonV