How should I finish?

Hi folks!

I'm about to start 2 new projects - "high end" corporate meeting openers.
Source tapes are shot on DVCam.
In both cases, the finished program will be projected onto a large screen
from a Betacam master (I think at the Javitz Center).

I've got the Igniter Uncompressed RT on a G4 867.
Ever since switching to OS X I no longer have Uncompressed Codec available,
because, according to Aurora, OS X is taking up too much resources
(drives are MORE than fast enough) so it seems that I only have MJPEG Online Codec
available in Igniter-land.

There will be lots of effects, layers, rendering, etc.

So here's my question:
Obviously, I'm going to do the initial cut "in DV"
But for the final master, should I do an "Online" as MJPEG,
because of all the rendering, especially considering Beta is
final destination? (I can look into whether they would be able
to project a DV master, but I think the client wants a Beta.)

Would it better to stay in DV, and just take the SVHS out from
my DSR-11 into the Beta Deck?

I greatly appreciate any thoughts, insights, opinions, experiences, etc.

Thanks,
Jesse Gordon