@CapeTownCloudChaser, it might help you, and be in your best interests, to take your flavors and mix them as single flavor tests (SFT's). Start with flavors you think you will like the most. That will help you.
When you were enjoying retail juices, what flavor profiles did you like best?
Finding similar mixes here or at ELR etc. should be helpful to you.
Start doing SFT's with those kinds of flavors. You will find, for example, that you might not like one company's strawberry but really like one or two from another company or two. Same is true for every flavor you have. Everyone likes different flavors. Not all flavors are created equally.
Some flavors just suck!
When I do SFT's I always start low with the %'s and do 5ml's. I set those aside to steep. A 5ml SFT will not require a month steeping time. Doesn't matter what kind of flavor it is (unless it's a Medicine Flower flavor). 2 weeks steeping for a 5ml SFT for cream and bakery flavors is fine. Why? Because you are only adding drops for any given flavor to 5ml's. The majority of fruits are shake and vape.
I start as low as 1% in 5ml base. Of course that depends on what flavor from what company. Sometimes it's less and sometimes it's more. It all depends on what flavor from what company.
There are exceptions to that. If I'm doing a flavor from Flavorah (FLV) or Medicine Flower (MF) I will only do a single drop or two. FLV and MF are very highly concentrated flavorings. Those are ultra concentrates. And those are two examples where you don't need much at all for an SFT (or in a mix). The same is very true for some flavorings by other companies.
The maximum % I've done an SFT for any flavor is 3%. And that's only for flavors that are considered non ultra concentrates. But again, it all depends.
I'm of the opinion that less is more with DIY. Other folks are different. Most of my mixes are less than 10% total flavoring. Many are less than that. Some are very low but those use ultra concentrated flavorings.
Some people like a higher total percent of flavoring in their mixes. There is no right or wrong. However, there is a point with every single flavor where if too much is used it will turn out bad (either taste like crap or be muted).
Doing SFT's is the only way you are going to know if you like an individual flavor. There are no shortcuts to learning which flavors you prefer. You could always do 2 or 3 flavor mixes (but...). Nothing beats getting to know your flavors individually.
I was taught from the beginning of my DIY journey to take very detailed notes. I still do that to this day with individual flavors and mixes. Nothing beats good notes.
Eventually everyone finds their favorite flavors and what works best for them with DIY. It takes time and much patience.
What works for me might not work for someone else and vice-versa.