Proposal: Lower Zcash block target spacing from 25s to 20s

The only risk is orphan rates, however, the latest stress-net measurements of 20s blocks is better than the expected ones in the original Zebra @ 25s post in May . It already meets the pre-existing safety bar established for 25s on today’s node software. Draft ZIP: Reduce Block Target Spacing from 25 to 20 Seconds A big goal of being the “cash” in Zcash, is to improve its usability. We have just hit the great milestone of reducing blocktime from 75s to 25s in NU7! In the original proposal, this was never the final target, just the next step. Its time for the step after this, reducing to 20s! This continues to improve end user UX and latency. The time to first confirmation improves, as does the time for back to back payments, onboarding and paying via near intents, etc. We conveniently have the perfect opportunity for the next step on latency and scale: Node teams have done the analysis and performance work required for this to achieve 25s We are likely to have a very small, lo