Optimize SMTP for Marketing

I run a marketing-email pipeline that sends large, time-sensitive campaigns and I’m hitting throughput and latency ceilings. I’d like an experienced SMTP engineer to walk me through performance-oriented best practices—everything from connection pooling, pipelining, and TLS session reuse to queue tuning and batching strategies—so I can squeeze more messages per hour without compromising deliverability. Current stack: Postfix on a VPS, DKIM/SPF already in place, list size 200 k+ per blast. Most guidance I find online is generic; what I need is concrete advice tailored to high-volume marketing sends. By project end I expect: • A concise checklist of server-side tweaks with exact config directives • Recommendations on hardware or hosting adjustments to remove bottlenecks • A brief plan for monitoring throughput and bounce rates so I can measure gains If additional insights on security or spam filtering emerge while we work, I’m happy to hear them, but raw send-speed optimization is the priority.