Flat-band graphene heterostructures host a diverse repertoire of correlated and topological phases, yet controlling them and representing them with predictive, quantitatively accurate models remains a major challenge. This talk traces the evolution from calibrated theory to insight, emphasizing phenomenological, data-constrained modeling for interpreting new measurements. I’ll begin with our development of local de Haas–van Alphen spectroscopy using scanning SQUID-on-tip (SOT) magnetometry, which maps thermodynamic quantum oscillations with sub-micron resolution. Starting from relatively simple devices (Bernal bilayer, ABA trilayer), I’ll show how these benchmarks - together with calibrated tight-binding/continuum models - establish a single-particle baseline and guide next-generation moiré samples. I’ll then turn to rhombohedral pentalayer graphene aligned to hBN (R5LG/hBN), where refined theory including sublattice-asymmetric tunneling and lattice relaxation explains striking orientation-dependent transport and SOT signatures. The central message is that hBN alignment orientation - a previously overlooked binary structural degree of freedom - reorganizes miniband isolation and the hierarchy of symmetry-broken phases. Finally, I’ll present a two-ξ device geometry that flips the alignment within one stack, enabling orientation-resolved tests and a reproducible protocol applicable to hBN-aligned graphite multilayers and twisted graphene multilayers.