Well last year I shot two blacktails at 659 and 664 with my friends 270wsm with a luepold CDS system, pretty simple to use.... I know shocking compared to all you rifle loonies that shoot 1000's of rounds a year. Id love to shoot more but I mainly use stick and string and I can shoot archery in the backyard.
I really like the 4.5-14 but feel it really requires a 50mm objective to get the most out of the 14X.
If you are going to stick with a 40mm objective and don't shoot a lot then a drop to 10X max might be a very good idea.
Not be the shot police but my personal opinion is that you should never take a shot at an animal you have not proven through extensive prior practice you are capable of making.
Using someone else's gun and dope is not the same thing as setting up your own rifle. Setting up your own rifle, properly, and learning to shoot it in different conditions will require much more than 2 boxes of ammo.
I suspect you know this but your previous post seemed to make light of the totality of what is involved in reliably hitting at distance. Pulling the trigger is usually one of the easier aspects.
Good luck.