Leaking from the bottom of the cone where it joins the battery....PCC has 2 small notches down one side......Liquid is a 70/30 PG/VG
Well that's a good start, the case is right. The liquid should work, what brand is it? Have you tried another tank and Atomizer?
Also make sure there is an air bubble at the opening of the tank when you install it. If there is liquid at the opening when you install the tank some liquid will leak out when the spike enters the tank. Just make that air bubble goes to the other end before you vape. Burning wicks taste terrible.
Have you burn the wick with no liquid? (You will know by that horrible taste)
You also should clean the cone between tanks. Also make sure you clean the connection in the battery. With the leaking i am sure there is fluid under the atomizer.
How much liquid are we talking about?