A button tool that you show will work. In LT you would provide the radius of tool and the code will be pre-compensated.
Have a look at page 8 of Appendix A and you can see how a tool was positioned to the work.
I would suggest that before spending money on some inserts, create different tools in in LT, using what you have, providing different tool
angles, etc and then generate some pathing. Say you have a triangle tool, you will see that at some angle and using a depth of cut not greater than the actual radius may be satisfactory for what you want to do. You can zoom in / see just how the tool is following the pathing and check for gouging of the tool. Try out the test tool location..........
Note that the tool is not shown to actual size...it will be bigger ..... but, you can still see the tool to stock relationship.
LT provides for gouge protection and will not provide a path into the work if it gouges. So you will see that a Button tool 1/8 radius will no go into a corner with a radius small than the radius of the button tool.
Have fun,
RICH