So, now you told us that "consider factors other than just the number of
instances (such as local routing connectivity)", but were are the
tangible recommendations? How shall the "local routing connectivity"
look like to be a good "local routing connectivity"? That is missing.
Some practical hints about network (ie. homogeneus transits, IX
connectivity, identical as-path ...) would be more useful - success is
seen by C-root.
[KDar01]: