I throw a Zone and Rhyno, so I am sure it is not so unusual to pair a fast overstable approach disc with a slower throwing putter.
Yeah, I have thrown a Scale and a Zone for years. Just recently tried the Harp and I prefer it to the Zone. But the Harp is closer in stability and feel to the Rhyno/Scale than is the Zone. And I am throwing BT Harps, one seasoned and one fresh, which cover a lot more shots than did my premium plastic Zones.