Total Commander

I would like to TabWidth number to be counted to the limit of Internal lister instead of one TAB.

That would not be enough.

<Tab>abc<Tab>d
gives a different line length than
<Tab>a<Tab>bcd

Also the usage of a proportional font may complicate line length calculation.

Just use an external lister.
Internal lister is fast (maybe because he does not compute such things? )

Regards
Holger