Miller, can't help with exactly what you're looking for. However, I'll offer this, directly from Roger Lees, proofmaster when the change was made from the 1925 rules to the 1954 ("tons") rules:

"The proof loads now set down in writing (in the 54 rules) are almost in every instance the proof loading in use under the 1925 rules. In general it may be said that under the new Rules of Proof no arm will receive a more severe proof than hitherto."