Also, bear in mind that if the Spirits hadn’t interfered in the Burrock Absorption, you’re looking at a much larger touman: the Blood Guard Keshik and Naval Reserve, Alpha, Beta, Delta, Kappa, Pi, and Omega Galaxies (FL), and Omicron, Sigma, Tau, Upsilon, Mu, and Rho Provisional Galaxies (SL).
The force I would use would be the blood guard which is a pure Mech force but as a standard practice the aero arm of the spirits their naval reserve separate to be assigned at need so assuming the spirit khans were in the strana mechty system how much aero forces would they roll with?
That’s entirely up to you, I suppose, as aerospace forces are attached on an as-needed basis.