Those quilts with a zillion small pieces sewn into 'flying geese' or 'half-square triangle' can be intimidating. Not only that, when the pattern asks for triple-digit quantities of them, I just moan. However, there are a few tricks...
This week I've rediscovered one in which you can make 4 flying geese at the same time. The first set of directions I found used 5" charm squares, but another author suggests 5 1/4." She gives full instructions, pictures, and the formula for different sizes. Here is a link that includes this method, plus three others, with charts to show how big to cut the pieces. Flying Geese Methods
As for the HST method, it makes 8, yes 8 of them at one shot. It works really well and I've not seen this one before (mainly because I never looked until falling in love with a pattern that needs a zillion of them).
In this method, the instructor uses a special ruler to draw the sewing lines, which is totally unnecessary. Just draw each line corner to opposite corner and sew 1/4" on either side of it. No need for that ruler/gadget.
Other videos and instructions give variations, like pressing seams open (don't like it because you can see the seam through the light triangle fabric). One has a different formula for the size of the square you need, and had I used it, mine would have been too small. The formula should be "finished size of HST x 2, plus 2" and this gives very little to trim off. So if you want a 2" finished HST, use two squares that measure: 2 x 2 = 4, plus 2" = 6". The link to the free video (at least it is free right now) HST - 8 at a time.
I've not cut the 4" centers yet, but this is my first stab at what I might do with them, an old familiar design, but there are many variations . . .