The question is, "How confident are you?" Me--I have never stripped a holding female. I would wait about 15-18 days after I notice her holding, then put her into another tank with lots of smaller rocks for the fry and a (mature, cycled) sponge filter. A day or so after she releases, I put her back into the regular tank.
When you say smaller tank, How small?? Too small, and you will stress her. Is there a filter?? Is it cycled?