Didn't you start this thread once already?
Something to remember is that with yeasties, you are dealing with living creatures...every fermentation is different
...you can split a batch in half put them in 2 identical carboys, and pitch equal amounts of yeast from the same starter...and have them act completely differently...for some reason on a subatomic level...think about it...yeasties are small...1 degree difference in temp to us, could be a 50 degree difference to them...one fermenter can be a couple degrees warmer because it's closer to a vent all the way across the room and the yeasties take off...
Someone, Grinder I think posted a pic once of 2 carboys touching each other, and one one of the carboys the krausen had formed only on the side that touched the other carboy...probably reacting to the heat of the first fermentation....
I've found that you should never assume anything where the yeasties are concerned except that they are in charge...not us...and they've been doing this beer making stuff for 5, 000 years...so basicially we just need to trust them, and not bug them...and give them plenty of time, and they will make us very very happy.
You could pitch yeast a in a beer today....then in a month make the same recipe, in the same fermenter, and pitch another packet of the same yeast strain, and it may behave entirely different...maybe because the yeast was simply from a different batch run.....the beer may taste exactly the same, but activity
during fermentation may be totally different. It may take longer to start, have a different krauzen shape, anything really.
So unless you repeat the exercise with each yeast strain multiple times and figure out the average, you can't assume it's gonna behave exactly the same time next time you use it...
And again the only accurate measurement of activity
is by your hydrometer....
If I were going to try something like this, I would do multiple tries of each yeast strain, and go by a daily or twice daily hydrometer reading (Along with fermentation temp at the time of hydro reading) and chart that..but like I said, it will only be a generalization any way.....not a bible of repeatable behavior...since when we are talking about living microorganisms
mother nature can be a fickle wench.
Good luck. And post your generalized