Changing tonnage is simple...got to the drive you have SH 4 installed on..for example...C:/UBI/SH/MODS/Trigger Maru/Data/Sea/BBYamato
You will see a .CFG file entitled BBYamato, usually at top, open with text editor, like notepad. You will see the tonnage. Change to desired tonnage, click save was, overwrite. Now, will have desired tonnage.
Make sure you back up the file first, just copy and paste to empty folder on desk top.
I would consult other sources if I were you besides wikipedia. While I love wiki and is a great reference/summary for things, should remember it can be edited by anyone and there are often (not on purpose) in many cases, errors, omissions etc.
Tonnage of Yamato is often listed in various sources as different, number i've encountered mostly is 69,988-tons.
Far as TMO goes...
I see you are using the original TMO and RSRD. Amazing mods, my favorites of all time. However, their original creators have not been active in the subsim community for some time and thus they are both outdated. For a maximum experience with TMO, I suggest installing my TMO Update.
I gave TMO a major update, including many new ships added to roster, ability to conduct realistic night surface attacks , a new campaign, which is inspired by RSRD for historical accuracy and much much more. V1.0 was released in September...next couple weeks I will be releasing V2.0 (and likely the final)
Here is a link (below) Make sure to check out the README for install details and changes.
https://www.subsim.com/radioroom/dow...o=file&id=5965