@muth The 300ml you have already made cost no more than $5 by my estimate (100 ML usually costs me about $1.75, with flavorings and the bottle making up the bulk). PG & VG cost under $10 a gallon. Is it worth the headache to do these calculations and make an additional 900mls? How much do you vape a week?
I try not to make more than 120 ML of any one recipe on a given day. Flavors might fade, the recipe might not come out as expected... small batches of 30 or 60 ML are a great way to do DIY allowing for variety and easy to store grab n go sized bottles. You could scrap this bottle and start over... its a learning lesson and the second go round will help remind for future batches.
If you are ready to dive deeper, here is my complicated suggestion. It might be hard to follow immediately but it really is as easy as trading Marvin Gardens and Baltic plus 2 Railroads for Boardwalk or Park Place. Also, search youtube for FRESH03 or New Amsterdam Vapes as well ad DIYorDIE videos. Frsh offered over a year of how to vids that take you through the creation process.
Look at e-liquidrecipes.com. There you will find a plethora of choices to make and information on the flavors you own, or might buy in the future. Search recipes by typing your favorite branded vapes for clone creations. Many exist. Or search by your flavor stash to see what you can make. There calculator definitely will help you fix the batch on hand if you decide to do that. YES, break it into a few smaller bottles. Add the vg needed. What you have made could be considered a 'ONE SHOT' which is something premixed that is later aded to a recipe. Hold the 300 ml as is and used as the starter for new batches. You will have to add more flavorings when you do that for if you begin with 30% of a one shot, that will only offer 30% of the original flavors used. So you need to add 70% more of the initial flavor %'s (if you added 5 Sweet Strawberry, the one shot would only account for 1.5% of Sweet Strawberry and that means you need to another 3.5% to the new batch... I'm just winging my math, the calculator will solve it all.
Create a recipe on elr using the numbers from this first go. Save that and next hit options on upper right of recipe page to see "Create One-shot". Add the One-shot to your flavor stash as a single flavor. Next create a new recipe with the correct numbers of your starting point recipe. Add the one shot as an additional flavor to that recipe. By doing this you will find that elr calculates exactly how much more of each flavor you need.