So I guess Brian Litz would just make it into that club, that is pretty hardcore as even with load data it can only surmise what chamber pressure will be as hot ambient temperatures or cooking a round in a hot chamber can push pressures up, along with compressed loading and magnum primers but we all know roughly what our loads are doing.
Some loading manuals do give ball park figures on CUP's or PSI chamber pressure V's load used.
I've never heard of someone being excluded from shooting because of this I mean as stated above use a higher value sight setting and put the gong sitting on top of the sight blade windage you can dope out using the edges of the sight blade.
They may be nice but they certainly are not going to get dedicated members, as a club like that sounds like every ones load is even more secretive than the Coke a Cola recipe.
Our club is very grass roots and helps newbies out by assigning a person to them to show them the ropes once they get the gist of things and proven to be safe in range practices then they are let go to shoot by themselves but only after a qualifying period and sanctioned by the committee to become a member.