redirecting old pages to new good, band & ugly ?

'ello.
If there is anyone left on 'ere I have a Question WRT the new site
(Shock horror)
Basically... all html pages are now dead links but SE's are still
showing them although yahoo has started to show new links and pages.

so..... it's pretty much an impossible task to do a 301 redirect for
every old catalogue page as there were about 6 or 700+ so....
if I do a 301 for an entire directory e.g.
RewriteRule ^bodybuilding-supplements/([a-z0-9-]+)(.htm)$
http://www.gymratz.co.uk/retail-supplements/ [L,R=301]

I know all currently listed pages will drop to the category page but how
would external links to existing pages fair.
What I'm saying is... if we had 4 external links going to 4 old pages
but the 301 says those links are now the same page would the links still
be accumulative or would 3 become valueless as being "duplicate
content" Admittedly customers would still follow the links from forums
etc but would it be a negative, a positive or indifferent ?
If that makes sense.
oh, FWIW all products are defined as being from base camp.
e.g. http://www.gymratz.co.uk/bodybuilding-supplements/item333.htm is
now simply
http://www.gymratz.co.uk/reflex-creapure-creatine-wholesale
however the category it's menu is listed as is off
http://www.gymratz.co.uk/retail-supplements/

I must have lost a few of you on this one.
:¬)

Thankyou most kindly.
Pete