"Is this a not so common approach to machining?"
Yes it is a very common way to machine. But you would need to use G41 or G42. So if
deskcnc does not support these codes then no you cant, which seems odd.
I can only suggest using 'machine compensation' when you output the gcode and running some tests to see if the profile you programmed changes when you input different dia's in your tool offset page.