Auto body repair & detailing: Referencing Replacement Core Support?, sheet metal screws, core support

Question
Long story short, "Junior" rear ended a car several months ago and I'm just now getting around to repairing my '97 Camry LE (2.2L + auto)

The core support, radiator, bumper cover/"grill", & electric fans are smoked. I dismantled everything, cut out the top half of the mangled core support. Since the lower part of the support is fine (and contained 75% of the spotwelds ), the plan is to just replace the upper section. I cut the spotwelds on the replacement to separate the halves and set the upper section in place... everything fits up well, but realized I have nothing to reference for height/length/angle! I'd like to check a couple measurements before tacking it all up and was wondering how the pro's figure it out when the original is mangled (no way to measure before beginning)?  

Answer
SET THE PIECE UP AND USE SHEET METAL SCREWS TO HOLD UPPER TIE BAR IN PLACE. THEN SET YOUR HEADLAMPS IN AND FRONT COVER.

SET HOOD AND SEE WHERE IT ALL FITS/NOT FITS.

THERE IS NO EASY WAY...SOME TECHS JUST REMOVE THE PART AND PLACE THE NEW PART IN THE SAME PLACE BUT WELD 2INCHES IN EITHER DIRECTION TO USE NEW METAL.

MIKE