I am no longer worried about the armhole and neckline being too low. After cutting a second front panel, with the neckline 1/2 inch higher and the shoulder straps moved in 1/4 inch, I sewed it to the mock-up and it looked terrible. Those changes were too much, the stays didn't look right. Attaching the longer straps did not solve the bow inward at the top back, so I took off almost 1/2 inch from the top of one of the back seams in a straight line to the waist. To maintain the chest measurement I added that 1/2 inch back in on the front piece, putting back exactly what I took off during the first alteration. I'll spare additional fitting pictures and just show the finished pattern.
Look how nicely the armhole curves flow together.
It's curves matching up like that that make patterning fun.
I am going to have the straps tie in back. There are many more stays patterns in the book and all the shoulder straps tie in front, so why not. And starting the straps at the front creates a nice, non-broken, neckline. I've also quit worrying if the back is high enough. The top back of the V&A stays is midway between the underarm and shoulder and that's about where mine is so I'm leaving it.
© Victoria & Albert Museum (museum number T.120-1969)