This working paper applies the Rotating Dynamic Geometry (RDG) methodology to distill the essential geometric constraints of two clinically indispensable but structurally elaborate natural product pharmacophores: the camptothecin quinoline-lactone motif and the vincristine indole-ester motif. By analyzing unforced bond length ratios derived from published X-ray crystallography and high-level DFT-optimized coordinates (B3LYP/6-31G(d,p)+D3(BJ)), this study identifies a naturally emerging "unity harmonic cluster" at their respective active sites. In both cases, binding-critical bonds express geometric self-similarity to within ~1% (deltas of 0.0014 to 0.007 Å). A reverse pathway framework is established, mapping out precise numeric constraint tables to guide the design of streamlined, cost-effective synthetic analogs that retain structural self-similarity while eliminating toxic, metabolically labile, and synthetically complex peripheral structures. Furthermore, a "Geometric Combination Protocol" is outlined to support a harmonious, multi-pathway oncology approach with reduced off-target bulk. INTEGRITY NOTICE: This paper strictly separates verified geometric observations from open hypotheses requiring laboratory validation. No clinical claims are made. This document is a hypothesis-generating working paper submitted for open peer and pharmacological review.