No problem, it all comes down to what you want to achieve. 2.000 links spread across 5 buffers is 400 links average per buffer, so still a nice boost. If you spread too thin results would suffer. Unfortunably it's impossible to do blasts as big as with blog comments or guestbooks with only contextuals from unique domains. If you're looking for tiering a shitload of buffers, just get a cheap price spam service that's like 90% trackbacks / comments / guestbooks and/or mediawikis