Actually, since I'm incredibly lazy, I would do the first part for the QST's (making the HST's).
But oversizee, like, starting with squares that are at least 9.5".
Then I'd take that HST block, draw a diagonal line - perpendicular to the sewn one - place it on top of a BLUE plain square.
Now sew 1/4" on each side of the line, and cut apart.
That way you don't even have to deal with any bias edges at all.
Then trim both down to perfect 8.5" UNFINISHED blocks.
Obviously, make a sample with some scraps to confirm the above. :mrgreen: