well here’s a bump but I did finally find an answer, it’s the -filter-iterations and -error-threshold options that did it for me (haven’t experimented to make sure it’s only those two)
autotrace -corner-always-threshold 10 -corner-surround 4 -corner-threshold 30 -despeckle-level 10 -despeckle-tightness 2.0 -error-threshold 0.1 -filter-iterations 0 -input-format bmp -line-reversion-threshold .01 -line-threshold 1 -noise-removal 0.99 -output-file output.svg -output-format svg -preserve-width -remove-adjacent-corners -tangent-surround 3 -width-weight-factor 1.0 input.bmp