Hope you get to use them where you are kapil!
The Jeffery you have is certainly a great old round & the Ferlach will certainly be the go to rifle being in .375H&H & .30/06.
I know there is a .375 flanged case, & it was used in doubles as the DR equivalent to the 375H&H. How heavy are your loads then being the H&H version(if you are allowed to reload), obviously being in a double they are restricted somewhat?
Lovey DR's by the way - bloody envious!
Cheers
93x64mm