You'll find that under 300 yds, unless the angle is pretty steep, there isn't much correction needed for angled shots. Especially if you're talking about deer sized vital areas.
Rock Chucks are another story though, once the angle gets over 15-20 degrees and shots get 300 or further, it pays to compensate some on those smaller targets.
The string and protractor works, but sometimes it's a little tough to sight down the straight edge and then turn the protractor sideways to view the string and the angle (gotta be careful to not lose the posistion) It's tougher still when the wind is blowing the string/weight around.
The angle indicators that mount on the scope or base are nice and handy. So are the rangefinders that show the angle to target
I am just a couple hours from RC if I go via Custer then Hill City.