Hmm. Meld is indeed very nice for interactive comparison, but it seems its directory comparison mode cannot create patches. It’s weird that this feature has been omitted.
One big diff is the usual approach, since then the patch can be applied with just one application of the patch command-line tool (which is in a sense the inverse of diff - it reads in a patch file, and applies the changes to a source tree).
Maybe it’s possible to create per-file diffs and then concatenate them into the same file*? Have to be careful with directory paths, though, if the files are in different directories.
(* as in: cat file1.patch file2.patch file3.patch >out.patch )
As for DirectRadioButton, I think rdb will have to comment on that 