Very interesting. This is NOT a GGTS issue, been vaping now for less then a week I realize several things. These refillable carts, no matter what kind, I have 801, 901, 501, but will exclude cartomizers, since you can refill them, but they are NOT designed for such.
I now understand why many like to drip. Two drops directly on the Atty. It seems like I have to put a few drops 2-3 into the refillable carts, almost every other vape. So dripping just saves the trouble. The weakest area seems to be the lack of proper wicking from the material in these refillable carts. Even with the "proper" amount of juice, the carts seem to act "DRY", very quickly, you get the "burnt" taste. I start off a new cart, with lets say 10 drops, on a 501. I then prime the atty with two drops. This starts nice, but too quickly, I get less vapor and the burnt taste. If the cart seems overloaded, then I put the GGTS down horizontally, if I seem to get a dry hit, I stand it up to let some juice drip down, it's just a GUESS. Now I realize why many try to find other types of filler for the carts, like tea bags, other types of foam. This seems to be a major area of poor materials not helping. Maybe I just expected to get more vaping time after loading the cart and prepping the atty, but it seems you have to add juice to the cart and atty all the time, which of course at some point can lead to over filling, but it's a fine line when you go too far.
I'm looking forward to Imeo's version #2 of the AFS, that seems like the best way to go. I've tried all the various atty's and carts, and it's a lot of work to get a good vape. So far the cartomizers are the least amount of work and monitoring, but as most know, they don't last too long, and cost too much to use all the time. So far it seems like using the refillable carts is just the same amount of work as it would be to drip. This is okay when at home and you have the time and desire, but on the road and at work, something like a good AFS seems like the way to go. These are just my first usage findings, I hope with a few more tips, things will get easier and better. Again, this has nothing to do with the GGTS, it works great, my findings would apply to any mod, the weakest link seems to be the cheap wicks in the refillable carts. They always seem like they are "overfilled" or "underfilled".