Do you mean the text size of the toolbars and menus, or the textsize of objects added to the chart by custom indicators and EAs?
A screenshot would help
I mean these numbers besides the charts for example
It depends on which wine you use but you can see if you can find anything that looks like this:
Configure wine settings
Then you get the control panel and look for the Graphics Tab:
On the graphics tab is a slider that you can drag to the right to adjust your screen settings.