Do you have access to or can you get Trapcode Particular? It’s a 3D particle system, respects AE’s 3d space. If you can there are some spark presets which would be a starting place.
Particular can use layers as emitters, so I would copy your flying text and create a version that was essentially just the outer edge of it. Then try to use that as my emitter. Also if you created the text in C4D it would be easy to tie a null to the text and export the data (AEC) to After Effects. Then in AE create lights(they can be used as emitters in particular) and have the sparks & smoke be generated from those emitters.
Red Giant allows you to use Particular as trial(watermarked), so there is no harm in downloading it and giving it a try.
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.