Show canned hints
Each paragraph describes a scientific process involving three or four components. The components are English words or phrases labelled with a number (which specifies the enumeration) and a letter (which will be used in the giant equation at the bottom).
From the properties of substances described in the paragraphs, and from the giant reaction at the bottom, you may have noticed that this puzzle is about chemistry.
Several words have similar lengths and letters, like HERO, HALO, HERO, and HUGO. In particular, HERO appears in a "simple" reaction when combining HUB and OAT. What might this be translated chemically?
The cross-word style definitions are intentionally embedded into the sentences to make their boundaries a bit more challenging to discern. For example, in this phrase:
become a liquid which should not be drunk, no matter the means (9, L).
L could either be a noun, a verb, an adjective, or an adverb, depending on where the boundary is. However, only one of them solves to a word that makes sense in context of the other two compounds in this paragraph.
After plugging in all the compounds into the giant reaction at the bottom, there should be some surplus reagants on the left side, which will need to be balanced, as the title suggests, by the mystery compound, "A Perfect Match".
After figuring out what the mystery compound should be stoichiometrically (it may not exist as a real compound, but its chemical formula can still be written down), try expressing it in different ways.
Let us start with something simple. Add the place where spokes meet (3, A) to a piece of granola (3, B), then heat the mixture to get a cape-wearing figure (4, C).
Empty the container, and while it is still hot, pour the tasty and sour neurally-advanced mollusks (11, D) into it to get a note exchangeable for currency in London (6, E), after fuming out the cable whose conductive components are separated by a dielectric (4, F).
Still keeping the heat on, allow a solid having the cadence of hypochondriac, apothecary, or serendipity (13, G) to interact with an observer of ESP and apparitional sightings (16, H), and wait until their interactions convert sunlight into ATP (15, I).
Transport an aural navigation system (5, J) to high altitudes, where it is exposed to the wet and slippery author known for a kyphotic protagonist (4, K) to become a liquid which should not be drunk, no matter the means (9, L).
Blow a magical curse (3, M) onto a Brazilian meat dish featuring beans (8, N) to get someone who might spread frightening news (10, O), who will be surrounded by a circle associated with Powers and Dominions (4, P).
Mix a symbol resembling 3 but with a curved-back tail in Tokyo (2, Q) with an antiquated communication method (3, R) - carefully handling the latter so that it does not touch anything else by accident - to find a Federalist who lost the presidential race to James Monroe (5, 4, S).
Lastly, add the MIT term subsuming the Mystery Hunt (3, T) to the exclamation of sailors approaching terra firma (2, U) to obtain a yellowish substance that raises a weighted load using a pulley system (6, V).
66A + B + 2D + 11½G + ½H + 21J + K + ½M + 3N + 3Q + 6R + 3T + 3U
32C + 3E + F + 11½I + L + 2O + 32P + 2S + 2V + A PERFECT MATCH!