The Color Glass Condensate (CGC) effective theory predicts the earliest stage of relativistic heavy-ion collisions to be a classical state characterized by strong color fields called Glasma. The dynamics of the Glasma are fully determined by the classical Yang-Mills (YM) equations, for which no analytic solution exists. In this talk, we demonstrate how we linearize the YM equations within the dilute limit [1], which allows us to express the field-strength tensor of the Glasma analytically as a three-dimensional integral. We solve this integral numerically to extract the energy-momentum tensor (EMT) of the full 3+1D Glasma at arbitrary values of rapidity considering nuclei of finite longitudinal width, away from the boost-invariant limit. This gives insight into the nontrivial rapidity structure of the EMT for the dilute Glasma. We also discuss prospects for simulating collisions with more realistic 3D nuclear models. [1] A. Ipp, D. Müller, S. Schlichting and P. Singh, Phys.Rev.D 104 (2021) 11, 114040 [arXiv:2109.05028]