I'm not sure what "tips" are being discussed. But I use empty plastic tips (no fluval) in them, to place on my 510/810/910's when dripping to act as "mouth piece", so as to avoid mouth to metal direct on atty. I have both flat and round, but the main reason I prefer "round", is due to the inside, I'll explain in a second. The flat tip is the one my mouth prefers, and feels better. But it seems due to the inside construction of all my plastic cart tips, the plastic inside is shaped like a "rectangle", and on some a small part of this deep plastic shell gets warped or slightly deformed if it is NOT aligned with the direction of the wire mess on the atty itself. Some of the wire mess atty's seem to be longer in one direction, horizontal/rectangular, and the plastic on the very end of the plastic tips must come in contact with the hot atty bridge, melting and deforming it. Therefore, I now try to align the rectangular part of the plastic cart tip to the rectangular shape of the atty bridge to avoid this from happening. The downside, is with a flat tip, the flat part is seldom aligned with the lips of my mouth in relationship to the way I like to hold the GGTS and button in hand. When using the totally round plastic cart mouth piece, I don't have to be concerned with the internal alignment once matched up, as the mouth end being round, allows me to hold the GGTS anyway I want, hence the only real reason I choose the "round" end tips. Not sure how the Super-T tips work on the inside in terms of atty alignment. Hope this makes sense, seems "drippers" know what I mean.
