Should feminine nouns and their adjectives be slenderised after prepositions?

The following prepositions govern a noun in the dative case –

In traditional Gaelic, a feminine singular noun governed by one of these prepositions was slenderised (where possible) –

In addition, any adjectives following these nouns were slenderised in sympathy –

However, in contemporary vernacular Gaelic, there is a tendency to avoid this kind of slenderisation, especially in the absence of an article –

Neither of these usages should be considered ungrammatical at this time –

Note finally that the following prepositions do not govern nouns in the dative case, so rules regarding slenderisation are different –