If you were making this how would you do it?
 

I think there are 4 shades here, 2 darks, 2 lights.
I want to use full pieces, not half square triangles.
I was gifted a couple of jelly rolls I can sort into light dark so if I start with 2.5" strips...

would they all be cut on a 45 degree angle, twice as long as wide I'm guessing?
layered all face up, OR right sides together, all (for instance) light on the bottom dark on top?

am I missing a much simpler idea or would I stitch them like a T-ish, bottom pointed left, top pointed down with 1/4" corners offset? I see I could also do y-seams which isn't a problem, but it sure slows the flow down...
I'd make some samples is my normal way of reinventing the wheel :) but one machine is at the spa and the other is packed in the RV because we are leaving tomorrow.

Or is it like looking at a quilt set on point, am I missing the obvious most simple solution?

These are cut as equal sided diamond shape, So they are 2.5' side to side for both parallel sides. For this pattern, I'd sew groups of four rows together, press and then subcut diagonal sections, being very careful to keep my seams on the correct diagonal. Then I'd sew those sections together into rows and sew the rows together - no y seams at all for me! I do this the same as I'd do a bargello, just with the strips cut diagonal instead of square with the seams.

The pattern I used to make my DD's quilt had similar angles. As per the instructions, I sewed strip sets together and then cut the blocks using a 60 degree ruler. As with the pattern you are trying to replicate, there were two mirror image angles that I had to be mindful of. Also, because one ends up with bias edges, great care must be taken with handling the long strips sets so that they do not stretch.

Look at the far left vertical strip. Forget about the angle and just look at the colours. You can see that it would be easy enough to sew the strips together (to save fabric, offset each strip) then use the 45 degree line on your ruler to cut them.

Also remember to stagger the strip sets where they start so you don't waste a lot of fabric with the first diagonal cut.

Agree ... sew strip sets together.
Then I'd make sure they were well pressed with starch or best press to prevent/minimizing stretching after they are cut on the angles. Sew each cut strip together and you're done!

What I see as the BIG challenge here is to get the right fabric tones/colours to get the 3D effect. Your photo really has accomplished that beyond belief!!

As stated sew your strip sets. Then either cut all one color set angled to the right at 2.5 inch and the other set cut angled to the left. If you want to cut one of each strip se together they probably need to be right sided together so you get mirror image. I would try this with scraps or paper to test this first

I agree with doing strip sets. If it was me, I'd starch the living daylights out of the fabric, sew the strips then cut. You shouldn't have many problems if you do it that way.

I tried doing this with paper -

Seemed to work - on paper, anyway!

The suggestion about staggering the strips so that you don't waste fabric is helpful.

strip sets. bangs head on table. Of Course! and Bear/Sharon, your drawing made things so clear about the shading and reverse cuts, thank you for taking the time do that, and thank you everyone for helping me think.

I AM The Starch Queen! I think we have a plan! thanks again, I knew multiple brains were better than just mine.
Looking for something not too complicated to work on while we are on the road for three months. Life is good, Sharyn

Is this the pattern? It is the same name as the picture posted above in your original post.

https://jordanfabrics.com/pages/crinkle-cut

There may be a tutorial available.

ETA: I just saw that you don't want to use HST. Sorry for the mix-up.