The video speak about url level 301ing not domain level. In my personal experience I estimate 90% of PR weight to pass from domain level 301s. If you file a domain name change in Web Master tools you should be able to retain nearly all page rank as you've made an open declaration of intent to Google so it's clear you're not trying to play sneaky games w/ 301 redirects.
There is a threshold that Matt Cutts talks about in other videos. If you use excessive amounts of 301's you will get flagged. If you plan to build links to multiple domains I and 301ing them I suggest you keep it at 5 or less, but you may be able to get away with more depending on a number of factors and if you use special tricks.
Example (Acceptable Use)
links built (75% of total) --> my-apple-farm.com
links built (10% of total) --> red-apples.com --> my-apple-farm.com
links built (5% of total) --> green-apples.com --> my-apple-farm.com
links built (5% of total) --> yellow-apples.com --> my-apple-farm.com
Example (Bad Use) #1
links built (10% of total) --> my-apple-farm.com
links built (40% of total) --> red-apples.com --> my-apple-farm.com
links built (20% of total) --> green-apples.com --> my-apple-farm.com
links built (40% of total) --> yellow-apples.com --> my-apple-farm.com
Example (Bad Use) #2
links built (1% of total) --> my-apple-farm.com
links built (99% of total) --> {insert 3,000 unique domains) --> my-apple-farm.com
Example (Bad Use) #3
links built (0% of total) --> my-apple-farm.com
links built (100% of total) --> {insert 3,000 unique domains) --> my-apple-farm.com
Matt Cutts also talks about how Google does this 301 strategy with typo domains. He goes on to state that doing so is okay, but it should not be the source of the majority of your links by any means. He also mentions that keyword stuffed domains for the sole purposes of manipulating page rank are bad. A couple is okay, but there are limits. Now, if you're trying to lock out competitors from getting good names in ur niche you can 301 all those names to your site, BUT avoid building links to that set of 301 domains.
