proper 301 redirects & google

how to redirect file names properly

[htdawg]

Hi,
Just a quick question.

Is it ok to use a general 301 redirect for a website if you change the names of the files so that if someone finds an old page in google search results it will redirect back to the home page of the site.

or will google think its spam?

I have seen examples where a client's site was deleted and his index page is redirected to a main folder and in the search results his page would show the title tage from the main folder.

eg.
www.mycompany. com/widgets/client/index.html
(redirected to)
www.mycompany/widgets/

or

www.clientsdomain. com/oldpage.html
becomes
www.clientsdomain. com/newpage.html

is it better to use a redirect that says

oldpage.html redirects to newpage.html

or just a simple redirect that just redirects to the index page if it cant find "oldpage.html"

would google have a problem for say duplicate content?

Also, I tried to find the proper way of redirection pages with a 301 htaccess redirect but i found different opinions
and ways (code) to do it.
Any suggestions?

Thanks