Adding convertible inner rockers

[Blueoval71]

I would like to add convertible inner rockers to my 71 coupe. Is there a tutorial or post that covers what is involved? I found this covering the 65-68's https://www.streetortrack.com/Installing-convertible-rockers-into-a-65-68-p-14.html but wasn't sure how similar it was to our generation. The only thing I could find here was http://www.7173mustangs.com/thread-1973-mustang-coupe-to-convertible-conversion?highlight=convertible+conversion

I assume that I will have to trim my existing seat pan to fit.

Any info would be greatly appreciated.