Question on how to measure for rear end width?

[brownz]

Im doing a mini tub on my 79 camaro, I have my rear wheels done 18*12 with 5.5bs,I have a moser 12 bolt that I need to cut down and need to know what the correct way to measure for the rear end width,



I talked to DSE and they run the same size rear wheels and tires on their sec gen's and they told me what they run for width end flange to end flange but am I safe to use that?



If I set my rear wheel up would it be best to have them in the center of the wheel well of to the inside or outside?



Any and all info is needed as i want to make sure that I'm doing this the best and correct way.



Thanks

Brandon