The only thing I can imagine is everything the other, more knowledgeable folks are asking and suggesting. When you go to create your recipe, the relevant stats show up under the recipe, like this.
So if you’re looking at the % circled in black it looks like 6.27% nic but that’s because I use 24mg/ml. Look at the amount circled in red, it’s 1.5 mg. Is it possible you misread the nic amount on that really harsh batch and it was just way too much nic?
For me 6mg would be too much in a subohming tank that drinks the juice down fast. I can vape 6mg in an RDA but only a few hits at a time and even then it doesn’t give me a harsh taste, just a dizzy head if I over do it.
if you mix the same mix without nic and get a nice vape but adding the nic in at a 6mg strength then it just could be the harshness of peppery tats of the nic. I think you are on the right track mixing a few sample bottles at 5ml and testing them.
Check out this thread for a few shake and vape recipes and keep the nic at the lowest percentages as possible to keep you off the cigs.
thats what i used.
i measured out the amounts in the first column (ml) so 8.3, 6.7, 7, 1.5.
@TheTinMan1 i dont have a very large selection of flavours. made the mistake of buying single flavours that sounded nice instead of ones that work in multiple recipes haha
The recipe looks right. And TRW may be on to something with the nic being stronger than labeled. The store bought juice could also have less nic than advertised or a ton of sweeteners in them to take away the harshness of the nic. You got any marshmallow, EM, cotton candy flavorings that you could add with the pear drops?
I think most of us have been there. If you haven’t already, check out this thread too to help you nail down some flavors to consider buying first.
You’re way ahead of me when I first started using the recipe side. With all the wisdom floating around in here, you’ll get to the bottom of it. 
will have a read through that before buying more, thanks (wont be buying anymore for a while tho as im skint haha).
Flavours i have are.
rainbow drops
black cherry
pear candy
sweetner
apple (granny smith)
realised these flavours arent amazing for combining 
going to make a 20ml of skittles and try 1 mg nic (found recipe from my stash)
hopefully tie me over till we get to the bottom of it 
Just to clarify…did you measure out 0.83ml or 8.3ml?
0.83 on a 1ml syringe sorry that was my typing errors
Here is another good read
The apple you have might go well with a little pear. And the sweetener at very low percentages may help the harshness.
yer. shook it for a min or so
Either that or the store bought juice is lower in nicotine than advertised.
Start with adding 4% Distilled water to save harsh stuff.
I have couple of idea hope they can help - let’s simplify this and take one step at a time…
we’ll try a lower nicotine level - your tank already burns a lot of juice per puff
if you’re not using a scale, let’s use drops - with thre regular eye-dropper, 1 ml is somewhere between 20 to 24 drops - let’s take 20 drops per ml and be on the safer side
we’ll mix your flavor at 10% ratio - then shake (or stir if you’re mixing in a small teacup like a sometimes do) - if it tastes too week, add 4 more drops (that’s another 2% in a 10ml tester), and re-taste - until you get the level that’s good for you.
so our base recipe would look like this - 7 drops of nic (if your nic strength is 72mg/ml), 20 drops flavor and the rest is your PG and VG. this produces a 2.5mg/ml nicotine
i had the same issue when i started - then i reset everything and started from small going up. re-calibrated my mixing method - all went well. no worries, you’ll get there quicker than you think.
Nic Juice 0.35ml 7drops
PG 1.65ml 33 drops
VG 7.0ml 140 drops
Pear Candy 1.0ml 20drops
@TheFlavorSeeker thank you for that advice!! Will give that a go tomorrow when I have a bit of time.
And thanks to everyone else for their comments and advice!!
Made something that’s tolerable for now to tie me over as ran out of everything else.
Ended up going to 3mg and it was a tiny bit too strong for my everyday vape as I tried it on my lower wattage one and it was ok.
Going to drop it to 2 or 1.5 I think.
Just need to find that base that I’m happy with and build on that
Again, thank you all for the help.