I got a PuriTank today. I have been using Protanks for about a year, and have been rebuilding coils and wicking them with P&C cotton yarn lately, with great success.
The flooding/gurgling is a common theme throughout this entire type of tank that uses these same heads. So far, for me at least, I have completely solved that problem by removing the flavor wick on a stock head and replacing it with some Peaches and Creme cotton yarn. The stuff is dirt cheap ( less than $2 for 120 yards) tastes fantastic, and anything from 6 cotton yarn "threads" (1 1/2 complete 4-strand yarn "pieces") to a full 2 pieces of yarn (8 strands total) in place of the original wick will completely solve the flooding.
I vape up to 100% VG myself
I took my PuriTank, simply popped in one of my rebuilt Protank heads, and the thing is great! No flooding, and so far exactly the same as my Protanks with the same head.