Spoiler: no lustrous syrup is teched here.

I spent a lot of effort looking at various intermediaries considering the "left-flag" shape here bad (especially worse than its mirror image "right-flag"). Then I realized I don't have to get the first input-intermediary triplex bond to end up in product, and this "left-flag" shape just does everything.

The shape being stable across products also means that only two of the tips needs to be fire and I can make the center be air and provide the air for Firework A, which lowers the demand of input suppression to meet what "left-flag" intermediary can provide.