Computing Shock travel

I have a problem that hopefully our collective intellect can solve. I am planning on adding the Tomken 2" kit to my 3" lift on my Cherokee. I am leaning towards the Tomken kit because it has shock extenders which should allow me to keep the Rancho 9000's I have on right now, and eventually go with the in cab controller. I am concerned about shock travel. Does anyone know how to come up with accurate measurements before I buy the lift kit? If the extra 2" kit makes the Rancho's unusable, then I will go a different route to get the height I would like.

Thanks in advance.

Jason

how do you plan on getting the height a different route. disconnect your shocks, flex out, and see how much extra you have at compress and extended length and if that will be enough to cover the extra 2"