Hello

I begin the preparations of my first game in Africa, and I'm not decided as for my rifle. I'm just sure it will built on a Mauser action. So I have 6 questions which require an answer :
1)Which are the differences between the 416 Rem. Mag and the 416 Rigby ? Can I fire the one in the chamber of the other one?
2)Which are the differences between the 375 H&H and the 375 Flanged ? Can I fire the one in the chamber of the other one?
3)Can I shot a 458 Win. Mag in the chamber of a 458 Lott ?
4)Are the BRNO rifles still product ? It seems to be very good rifles.
5)Are ejectors very superior than extractors with regard to safety, speed of reloading ?
6)Are twin triguers very superior than mono triguer with regard to safety, speed to reshoot ?

Thank you in advance for the answers

Cordially