I've had good luck with 3.5 gr of titegroup for a similar plated 124gr bullet.
Felt recoil to be in the medium to light medium range.
Cycled fine in the glock, sig and browning.
Did not play nice in the S&W929pc revolver.
Scroll down. I created a post on 124grn round nose Berrys. Sure there may be some info you could use.
Didn't like the idea of titegroup. It's a fast powder and didn't have a large loading window for a bullet that heavy. Went with WSF.
And I cant just measure the two bullets and subtract the difference because they mention the bullet is longer overall than the same weight RN.
Mgderf,
Yeah, that commend was vague. mea culpa
Loads with fast powders like titegroup contributed to the brass sticking in the titanium cylinder of the 929.
When I switched to a slower burning powder like Power Pistol, the "sticking" brass stopped.
Glad the OP found a good starting point for his load development.