I’m actually not afraid of printing things larger than a few square inches on the bed… Waited way too long for this. Tightening up the eccentric screws on the bed carriage so it doesn’t wobble also helps.
Although thinking about it I could clip the PEI to the glass giving it a flat bed…
Having had a similar issue, actual bed more warped than a TV preacher, and a dead, impossible to replace leveling sensor. I moved to a glass bed. But, now that you mention it, this seems like a great way to get then PEI adhesion and have the bed actually level. Just ordered some larger clips and I’m gonna try this out.