IMHO............it depends on what you call light.
If light is defined by being able to see through the bottle............the following could be included and IME last very well in cartos
*I have refilled my single coil smok tek mega in a tank 6 times over 5 days and it wicks beautifully with gooey better cake and same with BRPIC, butter rum pecan ice cream (extra nuts please for the nutty one)*
Gooey better cake
butter rum pecan ice cream
marionberry ice cream
In addition, I am a use and toss carto user. I use Boge 302s which are 801 compatible and smok tek dual coils, single coils and have never had wicking problems with any KBV e-liquids at their proprietary ratio of PG/VG. I do notice the draw gets tighter after day 3 with the darker liquids such as candy bar, OMG, caramel capp, but IMHO at the price, it is well below the cost of cigarettes and I love a new carto. I treat myself to new ones as often as I can afford cause *like L'oreal says* I'm worth it!