[gentoo-user] Still questions concerning a reasonable setup of a new system: UEFI &&/|| MTBR

Hi,

Since there is A LOT of stuff to read about UEFI, MTBR and hybrid
systems I want to sort out, what I need to read in advance.

The setup will be:

512 SSD carrying the root fs  with all directories with heavy write-loaded mounted
with/in/at/on/beneath/beyond/under/by/for (or whatever preposition is correct here 
... I am no native speaker, sorry :) tmpfs

One 3TB harddisc as a "data grave"

From what I read on the internet:
Everything bigger than 2TB needs to be GPT-formatted. 
Is there anything better than gparted for that job?

So I need to format the harddisc with a GPT.

The SSD:

1.) From the pure technical point of view: Is it possible to 
    format the SSD with a good ole MTB and boot the system
    from it and mount the hardisc (GPT) as usual?
2.) Is this reasonable?

Is this setup reasonable...any ideal/advice is very welcome!
Thanks a lot in advance!

Cheers!
Meino