I have four new sites, different themes, different IP addresses, no PR. I have the opportunity to link exchange with a webmaster who also has 4 sites, all the same theme, same c block IP addresses, PR5 link pages. Any opinions on the best way to link? The options I see are a) to link each of my site's to all 4 of the other webmasters sites for a total of 16 reciprocal links b) one reciprocal link from each of my sites to one of his sites for a total of 4 reciprocal links c)one link from each of my sites to each of his but mix them up so that they are not reciprocal. Personally I would go for a) but I'm not sure of the effect that the same c block IP addresses will have.
Go for a). On a few links like that the IP block isn't going to be an issue. And even if it was or is you aren't going to get penalized. The worst that may happen is that the links won't earn there full potential value.