Another build pending

Ok. Already had great success with my homebuilt cnc/router for milling billet. Now I have moved to NZ and cant get my machine for a fair while so planning on building another. Same Spec just bigger table, X and Y axis.

Planning on a 650x650x150 cutting area

This time I plan to use Hiwin linear rail instead of 25mm supported round rail. What size Linear should I be going with ? The bigger the better I suppose for rigidity ?

I have been looking at ready made Z axis :

https://www.aliexpress.com/item/4000...7%237558%23136

Are these any good ? thought it might save me some time and money to buy it already assembled. Might do this for the Y axis also (If they do the length).
Or are there better suppliers that anyone know of please ?