I don’t know if this will help or not, but you may certainly wish to try it.
If you’re not already, try using a bench with an adjustable back.
Recline it just a bit below 90 degrees so that when seated, you will lean back just a taste.
The slight backward lean feels more natural (for me & others I’ve talked with) than locking the back at a perfect right angle as I see some people use.
Think of standing military presses. The back is slightly arched, the torso is positioned under the bar, and the scapula rolls back a bit.
Now imagine trying to use that form standing with your back against a wall. You wouldn’t have enough room to maneuver your body to get the proper leverage.
Now replace “wall” with “90 degree bench” and you’ll see my point.
If you can find footage of Coleman and Priest doing seated db presses, you’ll see them using this same technique.
