I use McKenzie Drifter while fishing with another person, so flippers are not an option. If I really need to slow down my boat I use a 5 foot section of chain as my anchor. Works well and it never got stuck, but I always have a sharp knife handy and I don't use this system very often - maybe couple times per season (not the healthiest thing for the river bottom). We had few years ago anchor stuck on actual drift boat - it was dangerous and we had to cut ourselves loose. Flippers are a good idea and I use those on my Outlaw Rampage, but small size kickers are not very efficient, full size "Dave's Flip Fins" from Dave Scadden work much better.
Maciek