How do I configure Gmail in Mail.app to sync the mail messages with multiple clients?
You can configure Gmail as IMAP account type. That will sync your mail messages between multiple mail clients.

That leaves open your request to not retrieve all 3Gb of mail when first configuring the program. There I haven't got an answer only a possible workaround. Many mail clients limit their download sizes when they are on low bandwidth connections. You could try to limit your bandwidth, for exmample to 8 kbps, with these terminal commands when having Gmail configured to use secure imap:

$ sudo ipfw pipe 1 config bw 8kbit/s #create reduced bandwidth pipe
$ sudo ipfw add pipe 1 src-port imaps #sent traffic from imaps thru pipe


As Gmail is not offering an Exchange server, only ActiveSync compatible, you will never get an exact similar experience with Gmail.