We believe that in order to keep a campaign successful - it must have diversity. That being said - we strive for a 60/40 split.
60% DO FOLLOW (DF)
40% NO FOLLOW (NF)
The NFs create back link diversity and actual do give credence to the fact that you have so many links that are DF. Google sees this and takes it into account in our link building - thus allowing us to build MORE LINKS in LESS TIME because we have created social signals that do not "technically" benefit you for LINK JUICE.