I don't really change it up much between veg or flower anymore, as far as the ratios go. I just increase or decrease the overall strength if it looks like it needs it, no matter the growth stage. Sometimes i'll make higher strength batch for some plants, and simply dilute for others instead of mixing again. I don't add much epsom's salt either,unless I'm using RO or some other purified water, which isn't too often. I just add maybe 20-50PPMs worth when I do, sometimes. I mostly grow DWC, and usually run lower ec, or whatever they are asking for.. I prefer multiple lower EC feedings with any other system or medium too.
I've tried measuring out the exact numbers a few times, using my trusty old .5 scale TDS meter. The most recent measurements that I wrote down for the old 3.6-2.4-1.1 amounts came out to around 950-960 total, mixed properly and directly into a purified gallon jug of water from the store. I checked each time I added a part, but then again numbers change the more it dissolves, how many air bubbles, temps, etc and my measurements were different than the last times I checked. I haven't tried with the new 3.7-2.5 or whatever levels they recommend on the newer feed chart either, but it shouldn't be much different.. The part A brought it up to around 560. Then the epsom's @ 1.1 added roughly 100 PPM. Which means the calnit would be around 300 or so. I dunno, my meter might be different than everyones, but its close enough for the girls I grow with..
There are many variables that could change it up, especially measuring out only 3.6g for the test, for example. There could be more little chunks of one component in the little scoop of part A, which could throw it off by maybe 20 ppm or so.. I can think of more reasons its not the best test. Everyone has different water sources too, some might even need PH up or down, which adds a few points to the total. Stock concentrate will always be the same though once mixed. I used a cheap scale too, and it bounces around by a tenth, so who knows..
Probably better to use 3 gallons or more to measure out the exact levels with like I did, and triple the nutes.. It would be more equal of a reading, for part A anyway. Calnits not as big a deal, because its all the same stuff. I might go ahead and do that, along with the new 3.7 something-2.52 or whatever feeding levels they recommend these days..
Anyway, I have a chart with the target levels for each part I came up with a few years ago somewhere, without having to do the math, which is easy enough without once you know whats up. Until I find it, Here's the formula I been using to get the 3-2 ratio:
First figure out what you want your final target number to be. Say its 1000ppm (or 2.0 ec). Do you need Espoms? OK lets say you do, and you want to add 50 PPM. I subtract that from the total, so it would be 950. Lets say you don't need it though, and your water source (as well as whats already in part A) has enough mag and sulfer, I would just go ahead and call it 1000. They're just weeds anyway, and will tolerate a wide range
Now, to get the target you need for part A, you take the 1000, and divide it by 5 (to get the 500 or .5 scale I need for my tds meter) which is 200. Then, multiply that by 3. 600 is your first target number to reach, as you pour in your concentrate. You'll get used to how much to add eventually, and just go by volume if you want. I always want to double check anyway, which is why i just mix with my meter instead most the time.
To get the target for the Part B calnit, (basically you just add until you hit 1000 or whatever total, and don't really need to know the formula the way I mix with the meter) you just take the 1000 total and divide by 5 again, but this time multiply that by 2 instead of 3. 200x2 is 400.
So ya, 600 for A and 400 for B. Easy
800 total PPM w/o any epsoms for me would be:
Part A - 480
Part B - 320
If I was adding 50 ppm of epsom's it would be:
Part A - 450
Epsom's salt - 50
Part B - 300
Works good for me