I`m almost in the boat with mikld, but i do use my hardness tester to check for a consistent bhn ,BUT that gives me NO idea as to what is in my alloys.
These days , if the alloy is in the 12-13 bhn I pay more attention to size & good lube & loading techniques.
I figure if I can get a heavy for caliber 357 bullet going 1k fps & it`ll go where I point it to go it`s done what I needed.
But to actually answer your question is , alot depends on your particular alloy .
Tin, antimony, & arsenic content have affects on water quenching/heat treating that is very touchy & hard to do consistently .
I`ve done time testing on some alloys ( wheel weights & isotpe ) & found all of em go back to the original hardness in time .
Now , talking `bout timing of peak hardness depends on the alloys %s, COWW can vary greatly in this game now !!The isotope alloy was alot more consistent & predictable/controlable .
If I were to need a consistent alloy for a specific reason the alloys at Rotometals would be first on my list , now before we get on the cost ban wagon consider the alloy you need vs. guessing at the COWW you have on hand ,chasing tin/antimony & useable arsenic down & plus the alloy from Rotometals is ready to put in the pot ,no smelting/blending - - - - - see where I`m going ????
just my take .
GP