The key will be to assemble EVERYTHING, right panel, left panel, rear panel, match them together and match them to the top deck panel, match them to the bumper brackets, match them to the inner fender wells, everything that must be assembled together must work BEFORE YOU USE ANY ADHESIVE!
If you install any single part with adhesive and then find out later something won't fit because one part was 1/2" out of place, you will be pis*ed. Ask me how I know.
I didn't install the parts (in my car's case, the front inner fenderwells), but I paid the price of someone elses screw-up. It is documented well over many pages of my thread.
They affected the positioning of my front bumpers, front grill, hood, hood hinges had to be modified, lower splash shields and more. All this because of 1/2" misplacement.
Do it like Tim and it will come out fine.