Hi!
Why bother with meassuring trows....I don't!
Just go with what you are used to do before! This isn't rocket science you know...!
Most planes need just one or two centimeter trow meassured at the back of each flying surface, except rudder where you use as much trow as you can.
After the first flight ask yourself if you are sattiesfied with the planes behavoir and trim it if needed. It's very important that the C of g is changed so that trows can be minimized as much as possible,that means moving servos, batteries and other things as far rearward as possible.
Don´t complicate thing that don´t need to be complicated!