The banner is also going to hold back the model's airspeed so a model that flies well at a slower speed will retain more of it's control and have less risk of unexpected stalls. So go with the lighter model.

For towing you will not want to hook the banner at the tail like they do with full size banner and glider towing planes. Our models do not have the control power to pull the big drag loads like the full size ones do. Instead use the tow line attached up on the upper fuselage deck just behind the wing like model glider tow planes use. But you will want to prevent the tow line from getting caught up around the tail controls in near the fuselage. To avoid this the glider tow planes use lines arranged around the tail surfaces that look much like the old tail bracing wires on full sized airplanes. You'll want to pass these guard lines through the horizontal and vertical tails at about the 3/4 span point. And on the bottom the line should just go to the lowest fuselage point.