Soundboard selection can be difficult if you are new to guitar building. Learning to select good soundboards for your guitar is also difficult. Can someone really teach you to choose the right wood for your guitars and the way you build? I think not. It’s complicated. I just love these guys that devote entire videos to teaching you how to pick out wood or voicing tops for your guitars. Before listening to anyone ask yourself this, how can someone teach you to choose the right wood or voice your top if they can’t make a decent guitar themselves?
Picking out wood that will result in a good musical instrument is always to some degree a bit of a risk. If you have been paying attention to the characteristics in the wood you have been using and drawing some parallel to the sound you are getting you may with time arrive at a list of properties that will work for you. But its not that simple. There are a lot of variables to this equation.