I also see it all over the place, some to little, some to much. As you know it really needs to be just right, for to much will produce a muted, cottony flavor and to little will produce dry hits. Now here on the forums, I hear more of dry hit issues then muted, cottony flavor issues and for the most part that is caused by insufficient amounts in coil. Also as you know rayon is gaining popularity more and more and I can see why, for it is really a great wick. One reason why I personally like it is the extra time I get between rewicks, for if wicked correctly, it doesn't gunk as quickly as cotton. It also slightly edges cotton in vapor, wicking, and flavor imo. One thing with rayon however, is you cannot under wick it, and it needs full contact with the coil unless you will encounter dry hit. rayon doesn't swell when wet so it is different then cotton in that regard, but how I look at it is this, I install my cotton wicks anticipating a swell, and that swell vision thickness is how I wick my rayon dry. In the end, after saturation, both should be in full contact with coil, without it being to tight where juice is not being absorbed properly.