EasyPeezy raised a good point about making HST from strips. Using strips (and wanting to get HSTs the same size as the strip), means that you don't have the option of the two at a time HST method, where you use a larger square and sew on either side of the diagonal.
If you want to minimize waste, you need to be sewing trapezoids together. Here's a diagram that may be helpful.
The red lines are sewing lines, and gray lines are cutting lines. The first rectangle shows how to get two identical HSTs out of two strips. The second rectangle shows one way of getting a whole bunch of identical HSTs - with a bit of marking your sewing lines, you could sew all the seams in one go at your sewing machine.
Sewing on the bias is always a bit fussy. If your seam angle is a little bit off, you will get a shape that is slightly off from a true square. Because of the fussiness, many people (myself included!) like making HSTs a bit oversized and then trimming them down to exact size needed, which also makes the shape a true square. For anyone considering the strip approach to this quilt, I suggest making a handful sample HSTs at the very beginning and evaluating whether the size and shape of those HSTs meet your personal standards.