The filler will only appear wet if you fill the tank above the filler line. Gravitational Water Displacement theory would explain it. In non-jargon words - The liquid will be level both inside and outside of the carto. They will stay at roughly the same level.
These work great on carto's:
Acrylic Drip Tips and are just a tiny bit softer than the delrin ones.
Thanks Master, this is good info. I too would have expected the filler to look wet. And I'll second the recommendation on MV's new acrylic drip tips. In the past I'd mostly used the anodized. The acrylics feel better (softer) on the teeth, look nice with plenty of color options, and stay in the carto more securely.