helo.
i am new to this kind so please forgive any silly questions.

i have a BF20 L vario milling machine equivalent to Grizzly 704 and i want to convert to cnc. from my researh i found that nema 23 is probably enouth for x and y and 34 for Z
I am in Europe so it is easyer for me to find Leadshine products here.
my questions is regarding sizing between nema 23 and 34

1)because i think 2NM is small for x and y , is it ok if i use nema 34 about 4NM? it is the same length but my concerns are if it is as fast as the nema 23 because its larger moving mass at the rotor. Also i think that a nema 34 4Nm is cheaper than the nema23 3NM .

2) my second question is regarding Leadshines products and the ES-M and Cs-m series of motors. Do any of you guys have any experience on those? as i understand from the descriptions bpth are steppers with encoders so what is the diference?

i am questioning about the
CS-M22331-L - 3.1 N.m (439 Oz-In) NEMA 23 Closed Stepper Motor with 1000-Line Encoder
and
ES-M22430 (3Nm Holding Torque)

what is the diference ? it seems both aresteppers with encoders. the more expensive ES series seems that they have lower torque curve than Cs series . so why it is more expensive?

I appreciate any help.
thanks!