In most cases, a 4-2-1 manifold is better for torque without being too restrictive at high rpm - you could say the best compromise on the majority of engines.
However, on a naturally aspirated full race "screamer" engine, a 4-1 manifold with long primary pipes is normally used. Torque isn't of as much consequence when the powerband is very narrow and at very high rpm.
For any supercharged Eaton/G40, regardless of spec I'd choose a 4-2-1 manifold everytime. TBH, I've never seen a 4-1 option for the G40?
@djtez, I'd think that 60mm would be fine if that's what you want to make it from. Make sure first that the company making the exhaust have facilities to bend 60mm, it isn't a standard size.