"if you're gonna replace more than about 25% of any given panel, you're time, effort and ultimately money ahead to do the whole panel."
This is very true. Unless you have tons of free time and no money it makes no sense not to do a full pan. Its very easy to do and takes a fraction of the time than playing around with a bunch of individual patches. Yeah I have patched floors before but very small spots. Your car needs an entire floor, no way around it.
