Question on MultiSite Analytics, Domain Mapping, and more

Hi, Its me again with probably my million and first question ive posted lol

Anyway....I just installed multisite analytics today as I wanna offer statistics for my members as well as see them myself, a couple questions on it however.

1.) When signing up in google if I run domain mapping do I still pick the subdomain option or multiple domains...
2.) the code I get goes into the network admins spot but the main signup site...ie the primary site for the network... shoudl I get a 2nd code for that as well?

3.) Lastly... I saw some ppl saying you should get wp stats or something similar to see realtime statistics in the dashboard.... is that somthing that I should do or is analytics all I should offer?

Thank You