If I go without the swivel(which I do on a smaller flow), I'll attach the top of the float to the line and wrap the line around the bottom twice. This will hold the proper depth and put minimal wraps where the bobber and line come together.
When using the F-n-F in the creek it's different. If your wading or floating you stand the chance of hang-ups. Several hangups and reties in a row with the swivel can lead to high blood pressure and equipment breakage...LOL!!!!
In bigger water, such as Dale or Cland, I must reccomend the 3-way swivel.

This weekend I'll be on ole faithful with Big GW and Co(hopefully) and may go to the 1/32oz size with both weight and fly.

Billy