I like the hard pads under leather.

But a soft pad under leather can look and work well. (I don't think they look right on their own) In not too long a soft pad under leather will show where the leather bends as the soft pad gives. I don't find this objectionable. I use a soft pad, a Pachmeyer, under leather for a shotgun that sees high volume work in Argentina. Maybe 10,000 round and it going strong, but you can see where the leather flexes.

For the proper fitting of the pad, see JJ Perroduex through Chmplin Arms, where he shares space, or G&H in New Jersey.

Hope this helps.

JPK