I would use the fgmm brass, just don't waste much time on case match prep( uniforming pockets or flashhole deburr). While those steps are helpful on all brass, including lapua, on fgmm brass the primer pockets will be loose as a goose by the 3-4 reloading. Get some Winchester,lapua, or hornady match brass and prep them right. Should get 10-15 reloads with those mentioned brass.