Yeh 30-50 would have to be like a planetary alignment kind of situation.
So many ohter factors come into play. I've played with various settings over the last decade or so and only ever achieve a max of ~10 savings to various servers. I have heard of eastern coast people getting a better result, as well naturally their latency is lower to begin with.
One thing to remember all these steps to lower your latency will of course lower your throughput, so your downloads will be marginally slower, hence why I don't bother anymore as to save 8ms i went from 3.5mb down to 3.2 and that wasnt worth it
One of the best analogies I have ever read to do with playing with MTU size to reduce packet size and hence affecting pings is
"Say If I gave you a Jam donut weighting 100grams. Would it be any faster for your to take it from my hands if it only weights 80grams? No."