With new mixing ideas, I always start off with tiny batches & drops. That's fastest, easiest & least waste for me. In fact, it's 0 waste, unless I mix a real monstrosity (it happens). The key is, I know exactly how many drops/ml my syringes make, so it's very accurate and reproducible. When I want a larger batch, I use ml in the same ratios. For old favorites, I mix flavors-only, so I can quickly mix a batch to vape whenever I want.
There is some difference in the densities of various flavors, but it's rarely necessary to account for that in volume-versus-weight mixing. Alcohol-based flavorings are certainly an exception, but I don't use lots of them.
When I'm working on new recipes I usually use pro-tank-like knockoffs for the first round or two. I have heaps of them, always many going at any given time, for various in-progress projects. The coils are cheap (in bulk from China), and I go through MANY. Sometimes (rarely) I'll clean out the flavor with a soak in alcohol, then water; other times I'll vape unflavored (which I use regularly anyway to "clear my palate") until the residual flavor is gone; other times I just toss 'em. I used to rewick those, but with my general lack of coordination & eyesight it's like doing heart bypass surgery on a mouse, so I no longer bother. I've messed with fancier tanks & drippers, usually easier to rewick, but given that I find no better (and often less impressive) flavor, I always come back to reliable simple tanks for mixing new recipes.
Once I have a recipe I'm fairly pleased with, I finish with my favorite hardware. These days, it's usually eLeaf GS tanks.