The longer the stem the more stable the float BUT disadvantages are
1. It will pick up more surface skim unless it is is long enough to get down through that.
2 You will need special winders to put them on
3 they may even be too big for your box!
This latter one can be advantageous or a disadvantage depending upon what you want. If the stem is wire then float will take less shot down the line.
I used to make some really long wagglers for fishing a slow moving river where there always seemed to be an upstream wind that held a normal waggler up. To pick up what little flow there was I made these wagglers about 18 inches long but thin. I sunk the line as well. I did get a lot of snide commments when I used them but they did work for me.