For this, can I say - ar níos mó ná ócáid amháin - or is that too literal ? Would - ar ócáidí éagsúla - be more preferable here ?

I don't think you need the ar here:

níos mó ná ócáid amháin

But uair would probably do you as well:

níos mó ná uair amháin

Other options:

breis is uair amháin

níos mó ná an t-aon uair amháin

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Múinteoir Gaeilge - Irish Teacher
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect, but I can also speak Ulster and Munster Irish with native-level pronunciation.
Is fearr Gaeilge ḃriste ná Béarla cliste, cinnte, aċ i ḃfad níos fearr aríst í Gaeilge ḃinn ḃeo na nGaeltaċtaí.
Gaeilge Chonnacht (GC), go háraid Gaeilge Chois Fhairrge (GCF), Gaeilic Uladh (GU), Gaelainn na Mumhan (GM), agus Gaeilge an Chaighdeáin Oifigiúil (CO).

Ceart go leor, go raibh maith agat a chara.