Thin-walled structures fabricated via Fused Deposition Modeling (FDM) offer high strength-to-weight ratios and geometrically customisable configurations. This study examined how five hexagonal wall architectures of progressively increasing nodal connectivity (D1–D5), three layer heights (0.1, 0.2, and 0.3 mm), and two print angle orientations (0° and 90°) influence the compressive strength, energy absorption, and dimensional accuracy of nylon PA12 tubes under quasi-static uniaxial compression. A Taguchi L30 mixed orthogonal array was used to structure the 30 experimental runs, whereas signal-to-noise (S/N) analysis ranked parameter influence, and Grey Relational Analysis (GRA) resolved the competing compressive-strength and dimensional-accuracy objectives. The most complex architecture (D5) at 90°/0.1 mm achieved the highest compressive strength (144.75 MPa) and energy absorption (4.23 J), whereas the intermediate architecture (D3) at 0°/0.1 mm gave the lowest length error (0.03 mm). Layer height dominated compressive strength (S/N range 0.826 dB), and architected design governed dimensional accuracy (S/N range 4.162 dB). In the multi-response analysis, run T13 (D3/0°/0.1 mm) attained the highest grey relational grade (GRG = 0.8623), whilst the Taguchi main-effect analysis of GRG identified D5/90°/0.1 mm as the optimal factor-level combination, with layer height exerting the greatest combined influence.