A lot depends on how the hickory was handled off the stump. I've found over the years that any grain configuration makes a good hickory backing. Some of my first hickory backed bows had hickory backings that the grain was all over the place, some straight grain, some bias grain and some flat grain, some even had bad violations and none of them broke. The only hickory backing strip that failed was one that wasn't cared for properly for backing strips. It was fine for it's original use, a mantle. The way it was stored(for 2 years) was on blocks in a garage in log form. Rot had gotten to it(doesn't take long) and it broke across grain when first stressed.
I'm not saying to use any grain configuration for backing strips but try to find out how the wood was handled off the stump until you get it.
Figured wood is beautiful in risers and under glass but, IMO, shouldn't be used it building wood bows, either for backs, bellies or core lams.