I may have multiple options. I have never used a rotary tiller or the cultivator so really am not familiar with what those two options bring to the table.
If you can find a 1X16" plow reasonable I would jump on it. It will work good on that tractor, and with the small plot you're talking you can just plow it one-way and end up with only 1 dead furrow at the field edge. The older OEM plows are built better, but be sure you can get wear parts, like shares. It is almost impossible to find 12" shares for Dearborn/Ford, Oliver, MF, etc., that is why I say stick with a 1X16" used plow. DO NOT buy a used plow that requires shares that have to be sharpened in a forge by a blacksmith. You want the blade type throw-away shares similar to Oliver Raydex, IH Super Chief, etc, not the heavy, long nosed ones.
As others have said, if you are considering a 3 point rototiller be sure the tractor can run slow enough ground speed at high RPM .
A garden CULTIVATOR is light weight, low cost. Suitable for use in soil in good tilth. Tines are NOT spring protected. Designed to cultivate shallow; 4" to 6". Primary task is weed disruption in row crops. Usually pulled by 15-horsepower to 30-horsepower tractors.
A FIELD CULTIVATOR is medium weight and spring protected. It is a lightly built version of a spring-protected CHISEL PLOW but designed mostly for secondary cultivation in fields down to 12". However, will rip most moist loam soil, under most conditions, when number of tines and tractor traction are balanced. (I have NOT had success ripping hard packed pastures.) Available with 3-tines to 20-tines for tractors from 20-horsepower to 80 horsepower. Often used for soil aeration. A soil conditioner NOT a weed cultivator. (A good choice for game food plots.)
A CHISEL PLOW is a heavy implement used for primary cultivation. It is a conservation plow, which leaves 15% of surface vegetation intact to prevent wind and water erosion. Developed during the 1930's 'dust bowl' era in the plains states, to alleviate wind and water erosion. Usually pulled by 100-horsepower+ tractors.