In your engine, there is more than one thing that could be affected in a seized engine. In all my years, spraying penetrating spray on the pistons is futile at best. You need to understand that when the engine loses oil, the pistons somewhat “weld” to the cylinders, the bearing in the connecting rods in some cases can “weld” to the crank shaft and many other parts. I have seen enough seized engines to know that you won’t likely break the pistons loose and even if you do the damage is done and the engine needs to be replaced or rebuilt.