Thanks for the reassurances. I did visualize this decision as half the quilt being white triangles and I am ok with that as a design choice. Is funny how when I started in the 70s "of course" the background would be a solid white or muslin. Likewise, I have only myself to blame that for the last 5 or so years I've been specifically trying to use up my box of the tone on tones and the other box of very lights.
I am hoping for maybe some string piecing, the limited white on whites I have left along with some of my pale and especially pink on white background could still be incorporated but I had nowhere near the yardage or variety this project calls for.
Terry, I'd have to do some calculations on graph paper and counting on my fingers. I don't think you need to do anything but cut as Bonnie says/shows and then do the same trim on the other side. Back in the day I used to do a lot of "snubbing" off the dog ears as a way to help position the pieces, and then so they didn't stick up as I pressed open.
For this step, I'm going to be doing my cutting large triangles and slapping them on and then trimming. I also often use tape on my rulers, really helps with my vision issues as well as just consistency. Otherwise, I have the clear gridded plastic template material and I'll make a template/tool for the shape I want. You don't want to use this as a cutting guide but you position your ruler against it and use the ruler for the actual cut. Also, you don't want to get them near the iron.