yes you're correct in that elk come in many sizes and shapes. However, it's been my experience that the real world the diff between the thickness of the ribs and or the shoulder blade between them just isn't enough to sweat it.
Plus I've ran enough bullets from my 22/250 and Swifts thru shoulder blades to know that it just isn't that tough to punch thru them. Not at all saying that smallish rounds like these are a good place for many to go towards for elk for what's that worth..........
Just saying that big elk small elk there just isn't much diff in reducing them to the deep freeze.
The only remotely formidable bone on a shoulder elk is the knuckle, and in 43 years of elk killing and in being around elk killed I've seen it hit once and that was with my 270 and a 130 Sierra BT and it punched right thru and killed her just fine. Good bud who's killed a ton load of big bulls has hit it once, with a 165 Horn Bt out of his .308. That bullet punched right thru and flattened the bull...
Elk killing isn't rocket science unless one chooses to make it such! I've found that those that try to make it rocket science have a relatively small amount of elk work to their resume.
Now getting them back to the truck can be a whole nuther game