Which solution is best for a small CNC router

[szecho]

Hey,
because now I miss access to a CNC milling machine (in my previous job I had access to an "Ergwind MFG 4025" milling machine), I want to build my own CNC milling machine.

I want to use it mainly as a hobby and amateur (not 8 hours a day), to work mainly with aluminum - cutting emblems for classic cars, making custom details / parts, such as this air filter housing, etc.
https://www.instagram.com/p/1Objgml4py/

The cutters used are mainly diameter 1-3mm maybe 5-6 (with small depression)
Working area about 600 x 400 x 150 - but maybe a little bigger

Before I start buying parts and putting them together, I have a question for you which solution will be the best?

I am thinking of a solution similar to this:
https://www.instagram.com/p/B4iQNFeqwFu/


My assumptions are:
- lower base frame - aluminium extrusion profiles 80x80 Item or similar
- gantry profile - 80x160
- side support of the gantry made of aluminum plate (20mm?)
- one or two? ball screw 1605 for X axis
- spindle 2.2kW chinees
- hiwin linear rails

At the moment I have 4 hiwin qhh15ca Z0
whether to use them for the Y and Z axis, and for the X axis buy qhh20?
Or use them for X and Y and for Z buy qhh15ca ZA ?

That's it for the moment, if I remember something else, I will write it.
Are these my plans ok or should I change my assumptions?

Thanks for your help and best regards