I've never really used that thing as a bobber I've used it filled it with water left to buy the 4-ft leader off of the bottom of it and used it as weight to throw fly out there
I use a medium action rod - a reel with enough line capacity for bomb casts - and BPS high vis braid (4lb - 10lb test). I fill mine about 1/2 way. One thing that water bobber videos don't mention is the more water you put in the further you can cast...but also the smaller the above part gets. In windy or bright conditions you may not see your bobber. That is where the high vis line comes into play. Fun technique - who doesn't love seeing their "cork" go under! You can put a bunch of different options under the bobber - live bait, soft plastics or even flies