Inner Rocker / Floor Section

[Dustydog]

I am replacing the inner rocker panel on my 1970 GMC. My question is should I overlap the replacement panel or cut both the floor and replacement part and butt weld them together? The rust was only on the inner rocker, not on the floor. I have trimmed the original inner rocker back to where it joins the floor. The replacement part is temporarily on top of the original floor. Everything seems to fit well, I have test fit the outer rocker and even had the door on to check the gaps and all seem fine.
Looking for any suggestions on how to proceed.
Thanks!
Dusty