staining and varnishing is always a challenge, because, from a brand, a color, the result can vary a lot !
One good tip on that work is to use a big soft laquer brush. You can gently sand the board between the coats with very fine sandpaper too.
Don't forget to varnish (clear acrylic varnish, to avoid time yellowing) the board frame (if your stain is not a varnish too), because simple stain is quite fragile.
Personaly, I use nothing but acrylic or aquarethane products : they are a little pricey, but easiest (IMHO) to use than slovant based products. ANd it smells a lot less.
Good luck for the next steps, it's a huge and impressive board you're making
dimitri