Since you can't use the rotary cutter then use scissors to cut them apart. This might appear to be a dumb answer but I recently was doing blocks of half square triangles and would jump up to cut them apart at the cutting table with rotary cutter. I decided to sit at the machine and cut them apart with scissors. It was much easier, quicker and more accurate.....than the rotary cutting. If the squares are all acccurate to begin with then just do the HST and arrange in pinwheels or other blocks that use the HST.