3+2 machining using trivkins, where would I incorporate axis offsets?

Apologies if this is not in the right section. But I am in the works of completing a 5 axis mill and I am trying to wrap my head around mainly how to deal with the A axis offset. The A axis rotates about the Y axis and takes about a two inch dip off center. Where would I be able to compensate for this?  I have been reading around and it looks like xyzac-trt-kins has some parameters you can set in the hal file to compensate for this issue. Looking in the vismach sim files xyzac-trt.ini. I see things like line 65 : sets :y-offset 20. I dont see that when looking at trivkins. Is it up to the post processor to compensate for this offset? or do they both work together ? Could use some conceptual clarification. I would just use this mill for 3+2 machining just to get things stared but would love to eventually become a true five axis.

Thanks !

Alright thanks Andy! Ill get to work on how to incorporate that into my setup.