The actual traffic rate to le site is irrelevant.
All of those settings (except for "default TTL") seulement affect how frequently votre domain's secondary DNS servers poll le primary DNS server for updates.
If votre zone seulement changes infrequently (which Je crois yours does) alors votre value for "refresh" is currently a bit on le low side. Typically le primary should send a NOTIFY message to chaque of le secondaries whenever il y a an update at qui point le secondaries grab le zone file immediately. These days le "refresh / retry / expire" mechanism is seulement a backstop to that.
In tout event, c'est likely that votre DNS provider is automatically syncing changes to tous of le relevant DNS servers on le fly sans using DNS's built-in synchronisation mechanisms so le actual values are probably irrelevant.
Note that le "default TTL" field no longer means what it says. The real par défaut TTL is set (in BIND at least) avec le $TTL directive, et c'est seulement used quand there n'est pas an explicit TTL set on chaque record.
The "default TTL" field's meaning was changed in RFC 2308 et c'est actually a hint for negative caching. If votre server returns a negative response (e.g. NXDOMAIN ou NODATA) c'est how long le remote server should wait avant trying again.
The current value is a bit on le low side, mais il y a no harm leaving it as is. C'est often ignored anyway.
