Hi,
I would be bookmarking in pr2+sites only if you have 8-10 links to bookmark else all good bookmarking sites would be used.
Also I would be using 2 different accounts for bookmarking so that it does not look like spam to google.
This whole work can be done in 1day but the reason I mentioned three days is because if you bookmark all at a time it looks like spam to google.
The reason i am quoting low is because I am new to freelancing and want to build my own portfolio. I have 1+ year of experience in SEO, PPC, SMO and currently work as SEO and PPC Expert for my organization