Numeric column titles: In a table control we have columns with a number as title, e.g. "36". When we use this column title in GuiXT script commands such as

ColumnWidth [tablename,36] 8

GuiXT interpretes it as column number, which is correct according to the documentation. We could use the column number instead, e.g. write

ColumnWidth [tablename,122] 8

if column "36" is column number 122. Is there any other possibility?

You can use the technical SAP column name instead, e.g. VBAK-VBELN.  Press F1 on a table cell to get its technical column name.

With GuiXT 2014 Q2 1 and above you can use the notation '36' (single quotes) to tell GuiXT that you mean the column title, not the column number:

ColumnWidth [tablename,'36'] 8