Hello. I was wondering if someone could please help me figure out if mór has to be lenited here:

peann luaidhe + mór

Is it peann luaidhe mór or peann luaidhe mhór? I'm trying to say "big lead pencil." Luaidhe is a feminine noun and peann is masculine.

If it's peann luaidhe mór, then mór doesn't lenite because both luaidhe and mór are describing peann.

If it's peann luaidhe mhór, then mór lenites because luaidhe is acting as a noun and mór follows it as an adjective.

I think the first option (peann luaidhe mór) is correct, but I want to be sure.

peann lua mór (luaidhe is pronounced lua)

@djwebb2021 Thanks.