"cacra be li re pi mu" is better.

>>504

I would go with a conversion, because the second terbri of [zo cacra] is a duration, where the first one is just "X1 is an hour".

I guess it can be thought of as "two and a half type of hours".

the trick is, that the x1 of cacra is the thing that is x2 hours long, so {li re pi mu se cacra} or {cacra li re pi mu} is the best way of saying it.
if you say {re pi mu mei cacra} it means, that there are 2.5 things that are one (unless specified otherwise) hour in duration - that is, if your conversation partner won't hit you over the head for using a non-full number with mei ... even though that may make sense in some context? i have to ponder this :)