I'd do test batches and cut the baking soda by 1/4 each time.
That is make a whole batch of cookie dough w/o Baking Soda then devide the recipie into quarters and devide the backing soda the same way.
batch A (100% soda)
batch B (75% soda)
batch C (50% soda)
batch D (25% soda)
Use food...