EFI is certainly nice ( though it can be less reliable) but if you do end up going with a carbureted bike rejetting is not that big a deal if you have reasonable mechanical aptitude. You can probably get jetting suggestions from others on a motorcycle forum, from the folks at your local shop or the owners manual might have some basic suggestions. Otherwise you can just open the carb to see what you have and go a size leaner on the jets and needle position to adjust for the altitude. You can get it good enough ahead of time. You might be ok at 8-9k without doing anything but it won’t be ideal. It is good to learn how to tune the carb based on how the engine is performing and there is no guarantee the factory jetting will be perfect even at 800ft. The are some good resources online for generic carb tuning if you do a Google search.