I know everyone is different based on gear type of music and just personal preference but I really feel like lately the A4 is like the glue that brings together songs for me. Lately I’ve been composing between the DSI Pro2, Digitakt and A4 for finishing touches. The Pro 2 shares some blood with the OB6 with the filter and I think it goes really well with A4 sounds.
I’ve thought for a long time that the A4/K can wear two hats.
One, the jack of all trades. Finishing touches, drum fills, lots of various sound locked fix patches. All playing second fiddle to other gear.
Two, the lead. Using one track for full 4 voice poly, or (my favorite) one track mono will full 4 voice UNISON!
No sense in trying to make it wear both hats. That just diminishes its power.
The OB-6 has second to none pads. Such a deep timbre it engulfs you in its warmth. The A4 is much cooler but that could work well together.