The balance is important, very much so, in fact.
But so is the weight, hence the general tendancy towards UL weapons.
I've made some with the composite core and a counterweight (I used custom rolled brass rods with a lip on the end so they were the same size as the OD of the kitespar on the 1/8" that stuck out and snug on the ID for the rest of the 6") and I've made some without the counterweight.
In my opinion, the extra weight does not add enough balance to warrant it.
But, YMMV.