Hi,
I found that 115gr S&B works very reliably in my 1906-pattern KNIL luger. The 1937 S/42 likes them as well, but the ejector spring was aftermarket crap and broke. 1936 Mauser/DWM VoPo has had a life of reloading stuff and I'm now training it for S&B again
Just got in a box of 124gr S&B to see if the grouping improves.
As to OAL and kicking power, the S&B is very close to the original spec DWM rounds.
Geco 124gr 9mm works, but fouls up the pistol to an incredible degree, where S&B leaves no trace at all.