I've posted these thoughts elsewhere, but I thought I'd throw them here for folks looking to DIY.
When I first started this a couple of years ago, I did count by drops - many of my flavorings were in plastic squeeze bottles with a dripper top. Then I got bored counting
And, I moved on to flavorings that came in glass bottles (not so easy to squeeze)
Along with the philosophy of drop sizes not being consistent, I moved to measuring by volume. Even that is not precise for me. I eyeball the measurement in a disposable pipette. Because MOST of the recipes I utilize are forgiving, whether I'm off by smidgen here or there IS OF NO MATTER TO ME. There will be those who swear the recipe isn't right if it's not measured PRECISELY. My taste buds are MINE (as yours all are YOURS.) Even when cooking, if something calls for a quarter teaspoon of this or that, my measurement isn't 100% precise, and *I* can't tell the difference. Since I'm the one vaping what I make (or eating what I cook) - AIN'T A THANG!!!!
Besides, recipes should typically be viewed as STARTING POINTS. (Baking - that's a slightly different animal; one needs to be more precise or the end result could get seriously skewed....)
SO, the long and short of this is KEEP IT SIMPLE. ADJUST to YOUR taste preferences. There are some dynamite recipes out there, but there are certain ingredients I like more or less of. I have to ADJUST.
I measure my flavorings into a bottle. I add *MY* amount of nic, and then I fill up the rest of the bottle with whatever base of PG/VG - I tend toward 100 VG. SO, I'm not even getting a specific PG/VG ratio because the flavoring percentages are different from recipe to recipe.
Some of you have allergies/reactions to different components - some can't tolerate VG; others can't tolerate PG. MAKE MIXING YOUR OWN. If you need a specific PG or VG level, be more careful measuring. I typically mix in 30ml bottles. Sometimes I end up with 28ml to the amount of flavorings; sometimes I end up with 31ml because I can't/don't control the PRECISE spot where 30mL lands in my bottles.
I rarely have borked a mix so badly that I can't vape it. The one time I did, I'd picked up a 3mL pipette instead of a 1mL - oooooooo, that was STRONG!!!!! So, what to do? Get all the other flavors back in proprtion; split it into multiple bottles and add more unflavored base. Easy-peasy.
As Mattie says, this isn't rocket science. If you're unsure you're going to like a result, don't mix a 100ml bottle on your first try
I kept a lot of 10mL bottles from when I purchased my juice, just to have a playground. I'd rather throw out 10mL of skank for mere pennies per ml than to have to dump what could have been a month's supply of juice.
Sorry - got on a bit of a rant....