George's 8x4 router-me-bob

[JAZZCNC]

so with that in mind does the panel agree that screws are more accurate/ easier to mount etc- ie less faffing to get the tension/ pressure on the rack/ pinion?

YES

for the 'long' x axis (2500 ish) you'd just have the end block, the ball screw+ mounting block and the machined end bearing- plus the screw obviously-! (one set per side)

Your problem here with a ballscrew is the length, 2.5mtr is too long in my experience if unless you use a rotating ballnut.!! (Ask Jonathan regards rotating nuts)

would you go straight on with the stepper or do a belt?

I prefer using short timing belts to connect motors to help with resonance and allow easy gearing options.