Making styrene look like wood is a technique that takes time and practice to get the results you would like, and each of us has their own idea of what wood looks like.
I still like to build in wood, and I find the "yellow glues" are the best for wood. Elmer's Carpenters glue, or Titebond, are two brand names.
Back to styrene, consider...If you can actually see the grain in a 1/87 scale, or even in a 1/48 scale "board", it probably should have been replaced ten years ago. Look at any reasonably maintained wood siding, especially with a recent coat of paint on it. You won't see a whole lot of "grain". Weathering to the point where wood degradation is that visible, may be an impressive thing to see, but is indicative of wood that is about to fail catastrophicly. It may look "good" but would, in reality, be unsafe to operate. Damaged wood is one thing, rotted wood is alltogether another. Consider also, tool marks. Saw curfs, chisel marks, even marks from hammerheads, reduced 48 times, become virtually invisible.
I'll build 1/87 scale 28' whaleboats, plank on frame, in wood!...until I figure out the best way to do it in styrene.