Struggling with the stitchup on Chester Yawl

We’re at the stitching phase of our Chester Yawl build and have exactly the problem highlighted in Post: Chester Yawl Build - Stiching Question

Which was never answered.

In the same search I found this suggestion:

It’s pretty dated, but could still apply and seems to fit my sense of assembly. Basically, if the planks are cut to mate all along their curved edges and they all meet at two common places, the Bow and the Transom, then it seems that building from the keel up, ie, stitching the #1 planks together, Tying at the bow and the Transom, then adding each subsequent set of planks, one layer at a time, would naturally allow the planks to lay together without any distortion since the planks HAVE to bend properly to meet at the two ends.. When the planks had to be drilled in-situ, I could understand the published sequence, but now that they’re. predrilled (THANK YOU VERY MUCH FOR THAT!), then laying them on in sequence might be a workable approach.

What am I missing?