Sister sites link solutions

[jimpoo]

I'm running tens of websites, most of them are with 80 catalog pages links to 1000+ product pages.
All are use the following link structure:
HOMEPAGE<-->80 CATALOG PAGES<-->1000+ PRODUCT PAGES-->HOMEPAGE
Some of these sites are topic relevant.
One of them is PR5, three are PR4 while others are PR3 or PR2. The links on the homepage of the sites are 80 or more, but less than 100 (google guideline say links number should less than 100 on a page).

I'm thinking which way is the bset way to link these sister sites and boost the PR# on google, here are the solutions:
1. Place 10 links on the homepage.
Good: These 10 links could inherit the most PR values, because homepage PR value is the highest.
Bad: It will hurt the PR value of other 80 catalog pages and 1000+ product pages, because the 10 links share the homepage PR, the catalog and product pages then will inherit less PR, as they all link back to homepage, it will hurt homepage PR as well.

2. Place 10 links on every page.
This is the same as the first one solution, I saw many webmasters do like this way, as they want to boost their sites PR furthest.
Good or bad?

3. Place a 'partner' page on every page, then place the 10 links on the 'partner' page.
In this solution, homepage is the highest PR page, then the 'partner' page, and the 10 links share the PR of the 'partner' page. Is this a good solution to boost all sites PR furthest?

Are there any good solutions to boost all sister sites PR furthest?

Thank you!

[le_gber]

Be carefull when interlinking these sites together. You might end up with a link farm

Leo