Different plurals in different dictionaries

[Droigheann]

From a different thread:

[...] nouns ended up being masculine or feminine and in some cases (like muir), a bit of both.

There is no hard and fast generally accepted rule [...] (i.e. there is NO reliable data to tell you if bùth is masc or fem in such and such an area, mostly if you ask people they'll give you their personal impression).

[...] On the bright side, most speakers are aware that gender can fluctuate so it's unlikely to cause issues unless you happen to run into someone who is determined that only they are right.

Is something similar true about nouns' plurals? I'm asking because every now and then I come across a noun for which the two dictionaries I use most (Am Faclair Beag and Colin Mark's) give me different forms (usually for masculine nouns): cònaichean vs cònan, daltachan vs daltaichean, dùbhlain vs dùbhlanan, iarlan vs iarlaichean &c&c.

[GunChleoc]

There is also cànanan/cànain, dealbhan/deilbh ... it's a dialect rather than a gender thing.

Just like with verbam nouns where you have to remember whether it's -adh or -achadh - they can simply go one way or the other.

[akerbeltz]

Pick one and stick with it, basically, as with the endings of verbal nouns (seasamh, seasadh, seasachd...), most speakers are aware that there is a LOT of variation and will accept various forms.
The only pattern I've discerned is that plurals with -ain become more common in writing the further back you go, especially in disyllables i.e. the modern language is developing a preference for ending over palatalization. But that's as far as it goes.

[Droigheann]

Pick one and stick with it, basically, as with the endings of verbal nouns (seasamh, seasadh, seasachd...), most speakers are aware that there is a LOT of variation and will accept various forms.

That's the kind of advice/explanation a learner likes to hear.

The only pattern I've discerned is that plurals with -ain become more common in writing the further back you go, especially in disyllables i.e. the modern language is developing a preference for ending over palatalization. But that's as far as it goes.

And I find this convenient too, because I prefer the genitive and the plural to differ from each other. Mòran taing!

[Níall Beag]

..because I prefer the genitive and the plural to differ from each other. Mòran taing!

So does Gaelic, which is why genitive plurals are often the same as the nominative singular, to avoid such clashes. (!!)