Hi Robin! That’s a really great question!
If you follow the 1:5 ratio you can create a standardized oil that should be fairly consistent from batch to batch.
With that formula, you’d know that for every 5 ml of oil, you have 1 gram of calendula infused into it. (1/5, or 20%)
However, knowing the exact strength of various constituents present would be tricky without analysis, since harvests, etc can vary.
However, that’s much more granular data than most homemade or small businesses get into. :)