The foil is good with propulsion ive heard, but when I look at pictures of it, i see that the ankles are very spread apart, so i'd say to put in a tail... the wave or rapid are good ideas. If youre willing to spend a bit more, id suggest the fiberglass monofin from this website, its like the competitor and has awesome reviews!!! http://www.freedivinginstructors.com...&category_id=1
OR if thats too expensive and you don't like wave or rapid, maybe some on this website? the hydras http://www.scubastore.com/scuba-divi...onofins/1081/s
Good luck!