Contracting with the Little Dream Dragon did not affect Russell's current contract with the Shadowflame Dragon.
The Dragon Knight is the pinnacle of the Way of the Knight. In the Warm Age spanning five thousand years, Dragon Knights represented the ceiling of combat power.
There was no need to train, nor any room for advancement.
The strength of the Dragon Knight depended solely on how powerful the dragon itself was, so there was little difference between a contract of one day or ten years. There was no need for perfect mental synchrony, or any kind of balance of the spirit.
Above his head, scales erupted, and a throne materialized.
With a light leap, Russell stepped through the void and walked step by step onto the head of the Shadowflame Dragon, turned around, and sat down perfectly onto the throne, just as naturally and adeptly as he had in the Amber Dreamland on the throne of the Dreamscape Ancient Dragon.
Boom!