Fingers crossed for the EVOD! I haven't actually had any gurgling at all with the Protank. I used to get constant gurgling on the T3, though. There are a couple of things that can cause bottom coil systems to flood:
1. Drawing too hard.
2. Getting juice in the center tube.
3. High PG% juices wicking too fast.
1 & 2 are just plain bad luck. 3 is a bit trickier, because what can you really do about it apart from changing your juice? I've mainly been using a 50/50 PG/VG mix and, like I said, zero gurgling. I did run a couple of tanks of 70/30 juice through the Protank when I first got it, but haven't tried anything higher than that.
The one thing I would say is don't be afraid to really tighten the atomizer head onto to base of the Protank. If you tighten it too much, you'll cut off the supply of juice to the wicks and you'll get nothing but dry hits. You only need to back it off ever so slightly from that point to get the wicking process going again. My advice: use the knurling on the post of the atomizer head to tighten it all the way down onto the base - as far as you can go. Then back it off maybe a quarter turn or so (perhaps not even that much). If you get dry hits, back it off a little bit more and so on. You want that thing to be as tight as possible!
Anyway - I digress. To get rid of the gurgle all I used to do was decant the remaining juice into a bottle, take the whole thing apart, run a Q-tip up through the air hole and blow out the atomizer head. Problem solved!
I did a quick search to see if anybody had come up with anything else, and found this video:
Fighting the gurgle in the Kanger Protank eVod and T3. - YouTube
He's pretty much well doing the same things I used to do, just in a slightly more imaginative/creative way.
Hope that helps.
JJ