I just looked this up (after hearing this idiom just now in the latest Dexter episode). I found these on focloir.ie

make: to make the most of sth: leas a bhaint as rud, a mhór a dhéanamh de rud, súp a bhaint as rud
most: to make the most of sth (also to make the very most of sth) lántairbhe a bhaint as rud

de Bhaldraithe: a bhfuil ann a bhaint as
Ó Dónaill: Bhain siad gairmint as an bhféar garbh ('they made the most of the rough grass')
All of the dictionaries have a mhór a bhaint as rud, but this might be Béarlachas

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I'm an intermediate speaker of the Corca Dhuibhne dialect of Irish and also have knowledge on the old spelling
Soir gaċ síar, fé ḋeireaḋ thíar