I wanted to try a different way of operating the Z Axis so I setup a tower using 40x40. In the end it worked excellently and can easily print 60mm/s with 150mm/s travels. The coreXY is a very cool kinematic, and you can get some pretty great speed and accuracy. The main issue is the fact your Steps/mm are doubled, so the lower end motors don't like it at high speeds.

i had the ox build and wanted to do a more beeffer style so i went with a workbee style machine ..