Hey guys,
What are your thoughts about this build?

The workspace is 300x250x250mm. I would use 20mm linear guide on all axes (how strong precompression?) and 20mm 5mm pitch (2005) ballscrews with antibacklash nuts on all axes. The plates would be rotary ground steel plates. The Y axis "holder" would be filled with epoxy granite mix. Planning to use ER20 watercooled spindle. The motors are nema 34 servos.
Do you have a reccomended spindle or different collet type?
What should I improve on the design?
What controller should I use?
I attached the pics.