I use a custom spreadsheet that will tell me exactly what percentage of the total any given amount is. Or, it allows me to do it in reverse and let me specify that I want ingredient X to be 2.75% of the total, and it will tell me the amount needed (I just have to enter in the total amount of the blend and dilution that I want).
I think it's very very important to see what percentage of the concentrate any given component is. To me, seeing something like 25 drops of bergamot (well, I work in uL as drops is not very accurate, either, but that's another topic) in blend tells me nothing without calculating how many drops are in the total blend and what percentage those 25 drops would be. 25 drops in one blend may be 10%, in another it may be 3%, and yet in another it may be 25%.
Only by observing the various percentages of ingredients, and how those ingredients work together at that given percentage, do you really learn anything useful.