David Lawson at Wilderness Arrows could get you hooked up with some shafts or arrows depending on if you wanted to make your own. If your bow is going to be 90# @ 28" and you're drawing 27", then it's probably going to be about 85-86# at your draw. Also, since you could use an arrow that's only 28" to BOP, you'll cut another 5#'s of spine off your arrow selection. If the longbow is not cut very close to center, that could drop you another 5# of spine, so essentially you could be at 75-80# spine for that bow and your draw. That's a much easier spine weight to find (and gives you more options) than if you had a heavy point and longer draw which would put your spine need up around 100#.
Wilderness Arrows is a sponsor here so you can find their contact info under the sponsor section.