I had them use the sheeps foot roller on my pond, and I had a lot of rock. My pond is pretty wide, it's almost square. The roller did have issues with the rock. Also, the guys that built my pond had built lots of them, and they all held water, and none used a roller. There's good clay around me, just not at my place.. Ha!
It does sound like he knows what he's doing. Glad you finally got someone out there that appears to know what he's doing.

9 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (going away), SMB, and HSB (only one seen in 5 yrs) Restocked HSB (2020) Have seen one of these.
I think that's about all I should put in my little pond.
Otter attack in 2023