network vs. local printing: bandwidth & concurrency issues

We are running remote 3rd party Windows applications on Win 2k3 server(s)
over a T1 WAN/ 100 mbps LAN, via a netscreen VPN. Because the database
interface is so chatty (ISAMs), we've had to configure both Terminal
Services and Telnet interfaces for our applications. This works fine except
for printing.

So, with regard to printing, we've been experimenting with both local and
network printing. Previously, when we moved database traffic between the db
& application(s) over the WAN, application UI performance was sluggish but
printing from the remote print server was fine. Now we're moving UIs and
printing over the WAN and keeping the data access on the home LAN and
printing is slower.

Some of the Win2k3 Terminal Services experts have said that network printing
is the way to go, because instead of slogging binary data over the WAN, you
move smaller character based print files instead (which are then converted
to binary data at the remote print server, and then fed to the remote
printer on the remote LAN).

1) Our experiments indicate the binary data over the WAN configuration
(local printing to a remote printer over the WAN) consumes about 4 times as
much bandwidth as character printing over the WAN (network printing to a
remote print server over the WAN, and from there to the printer via a remote
LAN).

Is this bandwidth ratio ~constant ?

2) Our experiments also seem to indicate that local printing over the WAN is
asynchronous (the app spits the jobs & releases quickly), whereas network
printing over the WAN is synchronous (the printing app doesn't release until
the last print job is submitted to the queue, and multiple print jobs from
the application move through the print queue serially).

Does anyone know if there's a way to configure Win 2k3 network printing
to be able to support asynchronous printing,
like the "local" printers can ?

Thanks,

Steve