So the y-axis... I really think it needs to be bigger (surprise!) so, 'Y' not. My reconsideration of leaving the y axis as-is is due in part to heating considerations. The PCB heaters I will be using will be between 8 and 10" square. I am choosing these larger heaters because they are plentiful and cheap. And because I want a bigger Y. I think that 10" (250ish mm) should be big enough. For now.

The mods necessary to pull this off will include longer rails, and an extension on the y-bracing. Wiring will also need to be considered.

For now, however, I will leave the Y axis alone, but plan for the eventual upgrade by preparing a larger bed.