Do you have the trainer as well?
Can you close the No. 1 with both hands? You might be able to do some negatives with it, you just need to get it closed and be able to hold it or at least release it slowly (or as slow as you can

).
You can also do some partial reps with no set, deep set closes, strap holds with a lighter gripper or even do the holds with a cheap sporting goods store one.