GFO is a better packing because the impregnated Teflon allows less friction in the packing against the shaft. If a stuffing box isn't dripping, however (and opinions differ as to how much is enough), it isn't working. Without the drip, the packing would just get hotter and hotter, which can lead to problems a lot worse than a cup of water in the bilges. So get used to drips: You can slow them down, but if you motor
a lot, that's a bad idea. If you motor
for an hour and stop and touch the stuffing box and it's clearly hot to the touch, it's not allowing enough drips through, IMO.
I just installed a PSS in my steel
boat as part of a total drive-train replacement. It's impressive to see ZERO drips in the boat, but it will cost you two to three hundred bucks to achieve.