Can anyone show me bottom edge examples like what to look for in understand setting on the bottom up against a sheer wall but what sets one spot a part from the rest? Pictures would be great if possible

When there's a point that that sticks out from the wall or where it's undercut is where you have better luck.if there's food down there for a mink, id still set the straight wall if that's all there is,

Get the Ken Smythe/Bob Noonan book on it, it's really worth the read.

when trapping mink you want to hug verticle structure it can be as productive on land as it is in the water if you know what to look for where it really shines is when you have established ice
when you understand how they hunt and what time of year there after either mice or stageing white suckers in a creek it can be amazing to study the bottom of a creek and see a prominate run bumping the edge
of verticle stucture under the water that you would have never thought to look there before if you really want to understand the set pickup the book by Kenny Smythe called the bottom edge its a good read
and will answer any questions about the set that you might have
take care

I always leaned a large flat rock against the conibear giving the mink a tunnel of sorts to aim for. I would also set up the corners, and middle on both sides.

#150s on the corners, colony traps in the middle. .

I wish, not allowed colonies here in PA. 110S and 55s always served me well.

Dont have pictures but a couple more memorable ones that worked …
Drainage ditch with a couple feet of water. A tile draining into the ditch created a pool that was offset from the ditch. Put a 110 at the “corner” where the rats would turn from swimming along he ditch to turn into the pool and caught rats several nights in a row
Drainage ditch with a 90 degree bend. Put a 110 on both the inside and outside edges. The outside caught more rats than the inside. Picture nascar track and driver hugging the outside edge going around the curve.

Took me awhile to get it too. I feel with my boot under an overhanging bank until I find an obstruction, i set my trap tight to the obstruction on the bottom. I do it on the side of the stream with the most current. As the otter or mine mink hunts the overhang when they get to the obstruction they go around it. If it’s a bridge wall just set tight to it on the bottom. It’s like they’re walking on the bottom in that corner.