I know life is fucking you over in the ass, but I really want you to have fun and succeed with the gunslinger build because I think you'd enjoy it a lot and it's right up your alley.

Uh, some things I've found out from just reading the book.
There exists a Martial Art that is directly inspired by spaghetti westerns. The "Dollars Trilogy", Clint Eastwood, and The Man With No Name to be specific.
It's Righteous Devil Style (P. 450) and uses the settings version of guns: Firewands and Firepieces.
They deal insane damage but can only be used at close and short ranges.
But, on the other hand, they synergize with wizards very well.
They have the "Flame" tag, which means they don't use your *Strength* when rolling for withering damage, but rather apply a flat +4 damage.
This means during char gen, you can dump Strength as a stat.
Buying into the Martial Art requires 1 point in Brawl, the 4 dot merit Martial Artist, and then 4 dots in Martial Art: Righteous Devil Style.

Sorcery requires at least 3 dots in Occult and I think 1 merit.
It uses all 3 of the "Mental" attributes, so that you're going to benefit from making that your primary attribute, with the Physical traits your secondary (Get 5 dots in Dex. It's important. Dump Strength. 2 dots is fine.), and social attributes as your tertiary (appearance is the primary stat here but a balance is fine).
It also requires a Essence 2 charm to even have access to spells, so you have to supernal it, which lets you disregard Essence requirements for that ability's charms.
Out of the 5 castes, Twilights, the mages, and the Eclipses, the diplomats, have Occult as a caste ability, and hence can supernal it.