Work in good lighting.
Make sure you’re at a WS row before purling all the way across.
Ripping back 251 stitches would make even the hardest rock cry.
Large open lace requires a border that is at least mostly open as well to look decent, otherwise it looks strange. Or at least it does to me.
If you do something you think is pretty–like always slip the first stitch purlwise of your garter border–and you find a book that is all DON’T DO THAT ignore it. Do what you like, it’s your lace.