Ok, I am an absolute newb and know very little about this scene as I just got interested 3 days ago when I stepped on a disc and broke it. From what I have learned in the last 3 days I have a feeling that this tutorial is flawed as well as the wxRipper program itself. I am in no way trying to say I know more than anybody, I am just trying to help us all but if I am wrong then scrap everything I say here...
Every disc has a table of contents(TOC) at the beginning of the disk that tells the drive how big the disk is and what is on it. Xbox 360 games have a fake TOC at the beginning which trick any non xbox 360 drive into thinking its a small disk with some sort of DVD video on it. By swaping the disc in the wxRipper method you are simply grabing the TOC of a large movie and using it to grab the contents of the 360 disc which is why it needs to be bigger than the game. Its like a book, if you use the TOC of a smaller book that has 8 chapters to grab the info of a book that has 12 chapters you will miss the last 4 chapters because your TOC doesn't say they are there. Anyway, some games have 1 or more blank(dummy) sections somewhere in the middle of the disc which are causing read errors for us wxRipper users. Your movie TOC looks something like this
C19408
D1072
C109344
C1783936
J309472
C1783936
J0
but thats just a TOC for your movie and where there are dummy sections on that movie does not mean they are there on your game disc so when you change the first 3 lines in any TOC you may get away with it because your 360 game happens to have a fake movie dummy section at the beginning of the disc so skipping that data may not cause any problems with your game but now in this tutorial you are also skipping sections in the middle of the disc as well. You do know that when you get an error at something like C80886 of line 3 that you must have hit a dummy section of the disc and your tutorial here uses the solution "skip the rest of that section" but what if the dummy section was very small and now you have skipped some game data as well. who knows what this is gonna do to your game, it might boot fine and freeze half way through the game, it may not boot at all, it may get dirty disk errors. I think the only solution is to rewrite wxRipper to handle any read errors and flag that little byte of data as a dummy and attempt to continue where it left off. Again, I want to say that all this is based on what I have read over the last 3 days and I am a complete newb to this so maybe my theory is wrong.
Sorry for the long post and I hope this helps some how.