I also have that big Ark buoy, and it is perfect with your shoes on. But I tried it in the pool without a couple times, and it just floats too high and messes up the body position. My everyday go to buoy is the Eney buoy, and that one is perfect for me(168lbs). You can add water in it to lower it if need be, but then you are getting around the same float as the normal sponge buoys you get at the pool…
I have been doing a lot of just buoy swimming lately, really trying to focus on my High elbow and close to the body pulling. It makes it easier to focus if you dont have to kick. Trying to lessen my frontal drag, while not losing too much power…