At my desk...
A fine rifle like a Heym is always worth owning, imo. But if wear on an expensive, formerly pristine rifle causes you heartburn then maybe a Winchester is the rifle for you.
Africa is relatively easy on rifles, with endless fine dust being the culprit of rifle wear that needs attention. The fine dust plus sweat form a slurry that is hard on the bluing of rifles carried a lot, especially at the muzzle of rifles carried "African style." A sling will help, but if you're on your feet on tracks or walking dry rivers everyday you will end up carrying your rifle every possible way. Wiping your palms dry on your shorts or shirt helps some. A little post hunt evening maintenance helps too. With the generally low humidity a dry rifle is best, it picks up less dust. Its best to finish your evening clean up with with a good wipe down with a dry cloth to leave the rifle dry but slick. For bolt rails and similar, I found grease applied then wiped clean to be a good solution.
Alaska can be hard on rifles with humidity, rain and potential salt water being especially hard on blued rifles. A couple of oil wipes or an oily rag in a zip lock doesn't weigh much and can go a long way through a day. A good evening clean is required, with the rifle left well oiled. If the gun gets a soaking then stripping the bolt is a good idea, and maybe taking the action out of the stock to dry the underside and wipe it down. If the rifle is properly bedded (the Heym will be) then replacing the action in the stock and tightening action screws to the original tension will not result in significant POI change.
Don't know much about Canadian hunting.
For any Mauser or derivative actioned rifle, the following test ought to be performed - with an unloaded rifle, or course:
With the bolt closed and safety fully engaged, smack the bottom of the bolt handle, then try moving the safety to fire. It ought to move to fire, if it doesn't, it needs work so you don't get stomped, gored or eaten.
JJ Perodeau, a gun maker in Enid OK, can fix a rifle with a problem. If you're buying a new Hyem tell Double Gun Imports to make sure the rifle passes the test before it ships.
For any rifle taken into dangerous game territory, the feeding of your chosen ammunition ought to be checked. For African dangerous game hunting I would actually cycle every round of ammunition I was taking to Africa three times to ensure that it would feed in a pinch.