No, I don't really bother. It's up to the website as to what they wish to do.
The main thing is tp be natural and let what occurs, occur. The main point I mean to make in this piece is that you should post on sites that offer other benefits aside from a link and the dofollow benefits. All the other positives should be as much of a positive and the dofollow/nofollow benefit shouldn't weigh heavy at all.
To answer your last question - I would say just post here and syndicate - I personally think the more eyeballs the merrier :)