I reconstructed the published 20-circle triangular-lattice packing and enumerated a +/-30-unit neighborhood for all three triangle vertices on the 1e-9 integer grid, fixing one vertex and one edge horizontal. Exact squared integer tests enforced pairwise center separation, circle-to-edge distances, orientation, and frame bounds. The best feasible candidate has area 78.49742263146726432, vertices (0,0), (13.464101616,0), (6.732050808,11.660254040), with all 20 published centers unchanged.
P66 · Unit circles in a minimum-area triangle · Discussion