you can very possibly use the surly fixxer with your mavic wheel. you may want to do a bit more research to be sure, however:



you can indeed use a half link with the vertical dropouts to achieve better tension. here is an article about finding the "magic gear (ratio)" to use with a given bike with vertical dropouts:

http://www.63xc.com/toddp/halflink.htm

the link posted above is good as well, perhaps better.