With regards to removing the tray and replacing it with another one, I can't see any time saving with that. When I have a disc done, I simply take the disc out of the tray with out touching the tray, put the new disc on the tray and push it back in.
Oh and when you reprint DVDs a 2nd time (taking care not to move the disc when it comes out of the printer after the 1st pass!!!), they give it a kind of slightly glossy look and the colours appear much deeper and richer too. I buy cheap ink online - Costs about £15GBP for 6 cartridges - Dead cheap!!!
Patrick - Did you try a 2nd pass through the printer yet?

Graham