5 axis tool offset

Hi,

I have a 5 axis homemade machine xyzab...I get gcode from CNCToolkit in Gmax....works pretty well other than tool offset...My linuxcnc is set up in Trivkins...My questions..  I believe there is a 5 axis configuration...

Is it very involved to switch?

Can tool diameter offsets be used?

Would it be better to try and modify CNCToolkit post to use tool offset? 

I am going off a surface...x y offsets I can draw...the biggest issue is allowing for tool diameter in adjusting z axis for b movents.

Thanks for any help!!

Rick