I know we are all different but I have found I can deal with a weaker flavor more than a too strong flavor, so I would start weak. Before I started mixing, I vaped unflavored for a couple of days. Some people do this and are very content, but for me it wasn't working. But it gave me a starting point. I am now mixing down all the flavored nic
juice I have bought from them (same pg/vg ratio and nic strength), and I am extending my supply greatly.
Simple example. I love their zebra stripe premixed juice, but it is way to strong for me on the flavor. So I mix it with the same pg/vg nic mix unflavored and it is perfect. The ratio i use is about 20% flavored nic and the rest unflavored. At this point I am just trying to mask the unflavored "flavor" and spread my juices out.
As far as using straight flavorings, i would start very lean on the flavoring, and build up from the initial batch if you need too. But again for me too strong a flavor is worse than a too weak of a flavor. Everyone is so different here that you will have to play some to find out what you want.