I use unflavored 3mg 50/50 and still purchase from Nicoticket and That1Vape. I have experimented with DIY flavored concoctions, but I am a terrible cook and a terrible bartender, so my ejuice favors tend to be, well, terrible, too.
The best/fastest method to success in DIY is to start by getting to know your individual flavor concentrates all by themselves before trying them mixed with other flavors in "recipes". Simply start with your base of choice (PG/VG/Nic) and a percentage by volume of a flavor to get a feel for it, work up or down from there to suit your tastes. Realize that some flavors are very intense, a little goes a long ways with them. But it's easy enough to add more base to dilute flavor or more flavor to intensify it, find "your" preferred taste for it with the first batch. In the interest of time a quality UC is indispensable for DIY... mix and be vaping mostly aged within hours instead of weeks. Many flavors can be so good stand alone that you just might start vaping them as they are with no other flavors added. I do mostly intense liquids, but some of my often used ADV's are also stand alone. FWIW