Anyone have a pics/advice of attaching new walls?

I am doing a frame up restoration of my 57 Westerner. I am about to attach the walls to my chassis and have not been able to find good pics or many descriptions of the process. Mobiltec and Vikx have helped me so much and because of that I think I know what to do but it would make me a bit more confident if I could see some more photos to guide me. My walls attach to the sides of the chassis boards and I don't have much lip on the outriggers to support them so I rigged a couple 2x4s to hold the walls while I attach them. One of my questions is how do you make sure you have each wall at the same exact position at the front? My old walls were pretty rotted at the front so I didn't have much to measure and my pics don't help. It's probably pretty straight forward but if there are any folks with pics and/or advice, I'll take it! Thanks!