For the volume of launches you'd be doing auto tow would work just fine for FES. I also agree with Herb. A mini winch would be of limited utility. Why not go whole hog and take advantage of a full size winch for normal or non-FES launches? You would be helping your club and others and not just adding to your overhead. Maybe if you took on a mini winch as a self educational project for a boutique opperation and didn't care about additional utility or resale value it could be fun but again its hard to compete with auto tow with low launch numbers.
There's good and bad info about winching circulating in the U.S. I suggest looking to Europe for answers. Ask many questions and don't try to fill in the blanks yourself, that's why Americans have such a poor record on the matter.

-DT