I'm only using two kettles for a head-to-head. Didn't think of doing it on a daily. It would make more sense to have a big water kettle on another burner on the stove and just transfer water from that to the pouring kettle. However, if you need to justify the purchase, then yes I do recommend two pouring kettles.
The problem is that water here boils at 203 and I can not handle any water transfer other than from the kettle to the Kone. I usually do a pulse pour and quickly put the kettle back on the stove between pours to keep it at max temp. Even with this this I often struggle to keep it above 195.
With a single pour my water is hitting the grounds sub 200 and this does not account for any cooling from the Kone, V60, or environment.