The Large Synoptic Survey Telescope (LSST) will revolutionise our understanding of the extragalactic variable sky by discovering millions of transient detections per night. The key to fully exploiting this sample will be rapid spectroscopic classification of transients, combined with a systematic and well-controlled follow-up strategy. The Time-Domain Extragalactic Survey (TiDES) has secured a quarter million fibre hours on 4MOST (4-metre Multi-Object Spectroscopic Telescope) to follow up LSST transients and their host galaxies (Swann et al. 2019). TiDES is predicted to classify ~30,000 Type Ia supernovae (SNe Ia) and obtain redshift for ~50,000 hosts, this will be the largest spectroscopic sample of SNe Ia and their hosts ever collected. We will discuss our current simulations as well as our requirements for how photometric classification methods must evolve to ensure we can optimise our spectroscopic target selection for SNe Ia cosmology.