Toro's. and Talos's.
ideally in company sized caches in several locations. since at the time i'd not know that the Concordate would lose them entirely, i'd be working on the assumption that the government will fall if the war is lost, so i'd be pre-positioning caches of mechs and supplies to operate them to support a potential uprising against the Star League a few generations down the line.
so each cache would have a couple lances of Toro's and/or Talos's, spare parts and Missile/AC ammunition, as well as a few basic combat vehicles (say some scout cars or something) and large numbers of basic infantry gear (rifles, basic body armor, ammunition,etc)
i'd also have versions of the same type of caches with Aerospace fighters, and combat vehicles, scattered around on the same worlds.
i'd also be doing smaller caches with just infantry gear.