Do you need to replace, or reinforce the present channel ? Both jobs are very different, and must be addressed in a different way.
Let me know, and I will try and give you a few suggestions on how to go about it.
Thanks stepinwolf for the very detail repair procedure will use part of it,I have already removed the front end and the doors.To keep every thing in line on the doors I am making reinforcement bar to go from the hinge pillar to the lock pillar using the hinge and the lock bolts to securer reinforcement hopefully keeping door opening at same dimensions as before work was started.( I am sweating this one) I was planning that for the rear I could remove the lock pillar panel (on inside the rear wheel opening contains access cover for body mount) to get to lock pillar to channel at rear,the front end being already removed I think that I can get to the hinge pillar at front,Please give me your thoughts should have explained on my first post the point that i was starting from.