Re-dummying CDI files

[Beginner486]

Hi, I was very curious about the "dummying" part of creating a Dreamcast backup. I just wanted to see if it were possible to dummy a 74 min game to completely fill a 80 min. cdr. I really need your help with this since it is my first time openning image files and creating bootable cds. I have not gotten far, and I am a little lost when I got to the part of dummying and adding in new boot-file.

The file I am practicing with is DoA2LE, which is the only file I could find that is close to 74 mins.(73.3 mins).

This is what I have done so far:
1) I used Cdirip to convert the .cdi file to an .iso file, the LBA 11700.
the only setting used was -pregap.

2) I used Isofix version 1.3 to fix the file and I have three files - fix.iso, boot.bin, and header.iso.

3) Next, I used Isobuster v1.0 to extract the entire game, except for the Dummy data, into a folder called DOA2. (Is this part really needed, because from reading I found out that all data will reorgranized and it will read much slower on a DC)

From looking at all the DummyAdd programs all of them require a .cue file and .bin file. The reason why I didn't convert the .cdi into a .bin is because the game already has a dummy file and I needed to use Isofix to correct the .iso file.

Can it be possible use a .bin image and then remove a dummy and inject a bigger dummy file back into the .bin? After that, convert the .bin to a .iso and use Isofix 1.3? I read that the Bin2boot converter also changes isos into self-booting .cdi format.

Please help me if you can I would really appreciate it.

Thanks.