enicalyth,
This is not about flying at 4% CofG, it is about selecting 4% in the cruise page of the FMC. Getting to 35' or not has little to do with the cruise CofG selected in the FMC.
We leave the cruise CofG at the default 5% (wingletted 738). This gives the most conservative presentation of maximum cruise level, but has no influence on optimum cruise level. Just provides an extra bit of protection.