Why do you want to use sodium hydroxide? Sodium carbonate is safer, you can easily make it from sodium bicarbonate which you can buy in grocery shops, pharmacy or supermarkets. Check wiki on how to make it.
But yeah you could use sodium hydroxide, but you dont need to make the sodium hydroxide solution saturated, just add a teaspoon of sodium hydroxide to some water (500ml for example), and then once that's dissolved and cooled down, add that solution to the harmala solution slowly.