The precedent 240 will be a nice tug, as is the little Cub. You need a towrelease on the tug for safety.
Remember that you can't have enough power, and to keep everybody comfortable, put so much energy in to the tug (weight/speed/climbrate) that the glider is not in control.. 2ch gliders will often stabilize with long towlines, or given enough power just slowly pull them vertical.
For the Cub towing the old 2M, it probably will work out OK, but you won't know before you try.
