aakk9999 - 8:53 pm on Jun 24, 2013 (gmt 0)
I am not doing it manually. The plugin automates this depending on page requested. It looks for best possible (matchable) post and redirects user to that page.
Does this mean that as your blog changes (new pages added, existing pages updated), the new plugin can decide to do permanent redirect to a different post as the "best match" changed? I am not sure this is the best idea because this may leave your 301 redirect in the constant state of flux - for some time redirecting to one page, then starting to redirect to another, and so on.
With regards to returning 410, if URLs created with the original plugin (which created many URLs) have a common pattern that is unique and not found in your "good" URLs, then returning 410 can be just a few lines of code in .htaccess file.
In this case you could create a custom 410 page that would (for example) have links to your best or most popular posts in order to keep the visitor if he arrived via URL that now returns 410.
But I would question how many visitors you could get via these "bad" URLs because in order for visitors to arrive to these URLs previously created, then they have to be either:
a) indexed AND ranking for something in SERPs
c) linked from external site
d) visitor type in URL directly
I am not sure how likely is any of these.