I am 60 years old and don't have much strength in my legs. I do walk and I do ride a bicycle but I cramp easy and get winded with stiff fins. So far I have tried the ScubaPro Nova Sea Wings and they are Ok. Has anyone compared them to the Mares X-Stream and the Apeks RK3? For reference the Scuba Pro jet fins kill my legs in under 5 minutes...lol. They will be for single tank recreational diving both cold and warm water. Basically I need something very easy on the legs but still propels you when need be.