heard some trappers mention bending dogs down for there 1.5s in water sets and bending up for there land sets. Is there any real value to that?

Lots of people adjust pan tension with the bolt on the pan, in theory rust or debris can affect it. Supposedly take up the side to side play and yes, bend down after squaring off the end to make it a lighter tension. Bending up increases the pressure in the pan notch.

Bent down makes less pan tension
Bent up makes more pan tension

Check out the Fur fish Game series Tom Maranda did on YouTube a long time ago. He explains it on the fox and coyote series

I don’t like to bend the dog for pan tension, I use the pan bolt for that.

Me too bob.
On my old longs without pan tension bolts I just have filed short a crisp trigger short throw with less than 1/8" pan travel before it goes. Never had problem with toes catches maybe the bed a little lower like step down set keeps weight committed or something.
Had a few coyote and cat prints over the years right in dirt patter right over the pan without firing. I dont like too much tension would rather catch more cats in coyote sets with light tension or none.
Jim