heres a quick pointer that may help some
one side of that block will have an edge grain ( 1/4 grain) face on it, and you will want to cut your boards so that you have edge grain boards- thats the trick!
then you can take a pencil with not too sharp a point, and you can , by applying a little pressure, run a line down following the edge grain lines.
now shim that board so that that pencil line is parallel to your fence- then cut your blanks- now you have perfectly straight grained blanks.
if you build a sled for your saw ( table or bandsaw) which registers with the miter slot on your tables platen, you can clamp the flitch ( board) to the sled with toggle clamps, and get your pencil mark parallel to the fence using a tape measure, then you can cut perfect blanks.
after cutting the first blank, you now have a true straight edge- and can remove the flitch from the sled, and then just cut blanks against the fence.
IIRC, and from what i can see, that board has the edge grain on the large face side, so that will make cutting edge grain boards very difficult, so you can cut off a block at a reasonable size, that will allow you to cut decent manageable boards when you flip the block, to get the required edge grain boards.
this little bit of fooling around, will pay dividends and produce beautiful straight grained shafts.
good luck mate!