As hours flew by, we kept building more and more sophisticated fireworks than I'd planned.
At best this is a garden path sentence. Without the "...than I'd planned" it gets completely ambiguous and with wrong primary meaning different than intended.
Most people will read that as increasingly sophisticated.
My intention is to say both greater number and higher sophistication.
Is there a consistent recipe for neat rephrasing of this kind of sentences not to come out with "more and more [adj]" interpreted as "increasingly [adj]" but instead separating that into count and comparative, when the adjective has no '-er' comparative form?