: 1x8x16ft vertical grain (quarter sawn), or possibly plain-sawn planks.

Hi, I just wanted to point out that "quarter sawn" refers to a method of cutting planks from a log, not the grain orientation of the resulting planks.
Quarter cutting will yield plenty of what you refer to as vertical grain, but it will also produce planks with slab faces. And everything in between. Check the grain on the end of the plank to be sure you are getting the orientation you want.

Hope this helps,
Michelle