I could not agree more with this King P. As, the relationship between fluff amount in proportion to the wick size is also important.
I have found the Heron to wick incredibly. It is amazing as I have found a perfect relationship that allows me to vape hard without one dry hit.
Currently I am using just as P mentions and just moved one of the Heron's up to 2.5ish inches of fluff.
Never having much issue at all from gurgle, I think many are under the impression that it is just condensation. Some cases I have read the gurgling begins after a fill or build. This leads me to believe that it is from overfilling the Heron and pulling the juice into the chimney.
Look at your topper are there large juice puddles on the top? It is not condensation buildup after just a few draws. It is juice.
I also want to mention that I would much rather experience good wicking than poor wicking.
1) As many use a 1/16 inner diameter micro coil, obviously it limits our wick size.
2) Choice of wick, Most are using a form of cotton - many KGD or Cotton balls. The wick must slide through coil without resistance and I have found that sometimes my choice of wick of choice is too small to keep up with wicking(This is good! because I can alter wick).
Have you noticed the wicks small size fits through the topper with ample room for more wick? The chamber was designed for proportional wick's ability (x) flow of juice = X. *X=harmonious balance. This takes a bit of finding your perfect balance just like any other atomizer. I guarantee those with Kfuns, Sophias, drippers didnt nail your build for some time. Patience and practice as the Heron is an advanced vaping atomizer and a damn good one.
3) Fluff, as P mentions the amount of fluff is based on personal preference and as I mentioned it has to be in proportion to the wicks ability to wick at a constant and favorable measure.
Here are some photos of my coil and wicks(one or two have been posted prior but, information needs to be seen sometimes twice)
Here is a SnC wick. I spread out the tail to collect juice in well. No gurgle. This wick fits nicely through 1/16 coil and is sturdy to stand and with all cotton I am using the topper for extra lift. Wicks fantastic. 2 inches of fluff.
Notice the lack of juice on the deck! Its wicking GREAT!
KGD/balls are a bit more tricky due to the natural state of the medium. We've all seen it get limp and pathetic. I have an answer for you.
First here is another current build, 1/16 with KGD. Please note the juice on topper and the topper gap for the wick. A bit more juice on cap than prior due to the Heron wicking as it should but the wick can not totally keep up. I still love this build. No gurgling and a beautiful vape.
Here comes the kicker. *Please Note - This is not a Heron Issue!* This may be a quick fix for the KGD's wicking issue due to the forced small size of wick.
Anyway, I have used this method on other atomizers due to my love for micro coils and the restrictive sizes of cotton wick. I have tested this on the Heron and it also works like a dream if you need. It is simple and obvious.
Cut another strip of KGD and lay it on top of the existing coiled wick, juice it and replace topper and vape your brains out. It fills the gap nicely on the topper and provides more wicking at a quicker pace.
I would say my biggest point is to spend time with the Heron, I think you will find it as Great as I do, I hope this at least helps one person .
How come I dont see your coil in the 2nd to last pic?