I guess the EMER's on the Lee Enfield line are the product of over a 100+ years dealing with the Lee Enfield design and testing finding what works and what doesn't then throw in a few wars untold skirmishes with more learning all the while the armourers are compiling data to eventually be turned into the bibles for the 303 line.
The fountain of knowledge on these little jems is superb here and it is with honesty and integrity the advice is offered not only for the one asking the question but for all of us wanting to learn. TIA