If we were to only discuss things once around here the interaction and chance to advance new ideas would be more limited. I will offer my experience and opinion here regarding redundant pressure gauges.
Agreed on pretty much every point you've made. My question was specifically about transmitters on hoses vs. a direct connection. Using transmitters only or SPGs only both make sense to me. Adding SPGs as a "redundancy" to transmitters or putting button gauges on the first stage is a bad practice I'll avoid. To my original question, I sounds like the answer is to directly connect the transmitter to the first stage if the first stage has a HP port that sticks straight down so the transmitter doesn't stick out too far and if the tank neck allows for it. Otherwise, put the transmitter on a hose long enough to secure the transmitter under the top tank band.
Steve Davis covers the transmitter issue in a YouTube video here: