Need HELP to burn 35 DVDs very URGENT !!!

Question

I have created a 16/9 screen DVD, size 451 Mo.
Problem 1:
When I register it as Disk image, I cannot open it on my HD to preview before burn it. When I click on the icon, it says "specify application", so I put iDVD, but it doesn't open. So I burn my project directly from iDVD. It takes time. I need to burn 35!!! Is there is possibility to fixe it, or I have to encoder every time I have to burn the same DVD?
Problem 2:
When I burn my project to DVD-R x16 Verbatim, using "Optimal quality" or "Optimal performances", my quality image is suffering. Pixels are becoming too big (like 1mmx1mm mosaique), so it is difficult to read text and to see pictures. My original project is perfect. I thought I was DVD quality, because I was using DVD+R x16 verbatim. But it seems to be iDVD problem.
Thank to all who know anything about and can help. I have to deliver the project by the end of this week.

Answer 1

Problem 1 Follow these directions:
Suggest you create a disc image and then burn the DVD. File/Save As Disc Image...
http://docs.info.apple.com/article.html?artnum=164927
This will isolate any encoding/burning issues you may encounter. Once the disc image is created, double-click the .img and burn the virtual disc that should appear on your desktop, using Toast to burn the DVD. Disk Utility to burn the .img file. Usually, you can select a burning speed in Disk Utility.
There are variations to this process based on which OS X you are using...
Open Disk Utility (in Utilities folder in Applications folder), click on the virtual disc (maybe the .img) in the left-hand window. Click the Burn icon. A new window should drop down and your SuperDrive tray will open after clicking the Burn icon. Insert a recordable DVD. (Verbatim DVD-R preferred by me.) Click the Close button. Wait. Select a burn speed. Then click the Burn button.
-->If the virtual disk selection won't allow you to click the Burn icon, use the .img file instead. This may have changed in 10.3.9 and did change in Tiger.
Also, you can use DVD Player to play the virtual disk to check your iDVD project before burning to DVD. Launch DVD Player. File/Open VIDEO_TS (Open DVD Media... in Player 4.6). Find the VIDEO_TS folder and open that. (The audio folder is for DVD-Audio disks.)
http://docs.info.apple.com/article.html?artnum=93006
Problem 2 Burn the disk image with Disk Utility and select a speed 4X or slower from the speed pop-up.
G4 DP 1.25 GHz 2GB RAM 4 Drives 770GB   Mac OS X (10.4.6)   2 SuperDrives (SL 8X & DL 16X)