spark-ds41f is the best-engineered DeepSeek-V4.1-Flash recipe in the DGX Spark community and lands within about 10% of our 4-node SGLang ring lane on decode, but its 2-3x KV-cache edge is welded to a 64 KiB-page kernel and a non-NCCL transport that would break our three-lane switching contract. Verdict: keep our vehicle, steal their benchmark methodology.