Investigate default number of nodes for propagation utility interpolants

[Jean1995]

As discussed in PR #281:

In old PROPOSAL versions, the default number of nodes for the interpolation tables in the utility interpolants has been 1000. For PROPOSAL 7, we changed this default to be 500.

We introduced a way to change this number in #281 - However, we should investigate whether this new default is appropriate or whether we should change it back to a higher number.