The 7 Saum is easy button, 2880-2930 with 180gr hybrids with Rl23 or H4831sc from 26" barrels. With a 30" you could go up to next node around 3k or stay at 2900 and run lower psi. I've had 3 Sherman cases and none have done what Rich advertised. His velocity numbers are based upon Bat actions run hot with N570 and rl26, high energy throat burning powders that are usually very difficult to find. Idk how a case that gains 5% capacity somehow magically gains 7% velocity, it don't work that way. He's just running very high chamber pressures.
The best 7 Saum, and Sherman brass is all made by ADG, and its scarce, so when available buy all you can. If you take a Saum, SS, SSmax and load all to same chamber pressure, there will be maybe a 60fps window covering all 3. Rich has revised reamers and dies a few times now.
7prc short, it works well, will be 50 fps behind a Saum, donuts will be an issue as you're making neck from shoulder brass which is thicker and will need turned or you run long freebore to keep the bullet base above. Keep in mind that most people are using chambers with a 535 diameter at the 200 line to eliminate clickers in higher pressure loads.
7prc long, this case is a good design, but unfortunately doesn't have the industry support yet with readily avaliable "quality" components. Peterson will likely be first to market with 7prc brass, as they already have 65 and 300, it's my belief they also manufacture the lapua prc variations as well. The extra boiler room of this cartridge allows for more velocity, at the expense of barrel life. Also likely to need a 535 chamber at 200 line.
My recommendation would be 7saum using an 8.5tw barrel with 180 hybrids or 175 elite hunter bullets with a freebore around 180-200 in length. A friend of mine has this setup and all 3 of his barrels have ran the 180 at 2930 jumping 20k with RL23 and routinely prints groups at 600y around 2".