[O] Best way to implement project specific captures

[Richard Riley]

Currently I maintain a datetree journal capture using a template so

,----
|                             ("j" "journal" entry (file+datetree "journal.org")
|                              "* %?\n\t:PROPERTIES:\n\t:DateCreated: 
%T\n\t:Link: %a\n\t:END:\n")
`----

I also use j rockways' eproject set up that allows a hook to be run when
a file is opened inside a "project". e.g

,----
| (add-hook 'web-project-file-visit-hook '(lambda ()
|                                         (ignore-errors
|                                           (message "Web Project : %s" 
eproject-root)
|                                           )))
`----

where "web-project" is created this:-

,----
| (define-project-type web (generic)
|   (look-for "plan.org")
|   :relevant-files ("\\.php$" "\\.js$" "\\.org$" "\\.sql$" "\\.css$" 
"authinfo" "vhost"))
`----

So whenever I open a file in a directory hierarchy which contains a
plan.org matching those types then my web-project-file-visit-hook is run.

What is the best emacs/elisp approach to setting a capture file
destination specific to a particular project? THe main point being that
the default capture template above should only be replaced if I am
actually in a "project" : any capture done in a file NOT contained
within a project should default to the capture template above. Is it
someting to do with buffer-locals perhaps or is there a
better/alternative way? e.g Perhaps "journal.org" becomes a variable and
this is overwritten (or whatever the elisp jargon is) in the project
hook as a buffer local?

Hope was clear!

regards

r.