Easy way to do subframe connectors is with the floors out. Kinda kills two birds with one stone....Adds structural support and keeps everything in line.
thought about doing it that way but the thing that bugs me is you now lost the exact drop in your floor and might have to do some cutting in order for the new pan to fit.
I plan to weld mine in under the floors as 132068Dodge has done in his rebuild under the restoration thread. Then pull the floor, weld in new floor, then pull rocker and prior to weld, make sure doors fit properly.