Easy, good question....................
I've used elevations in WmR% but more in a failure swing type of method or a "W" bottom, using the break of the middle peak of the "W" as en entry signal. Then started using the actual elevations in reference to the support resistance levels in price. Never looked at actual hard number elevations such as -40 or -60 that you have touched on but rather more precise as in relation to each specific security and will vary.

RSI I believe to be more of a leading indicator and find many times breaks in trendlines of RSI will precede breaks in trendlines on price and offer early entries or exits if holding long which I admit I need work on (the sell side). Particular in triangles and/or channels. It is not a perfect scenario and can break false as well so stops are to be employed. I am paying closer attention to particular "cardinal" elevations as you have led me to, particularly the 50 level in RSI so I thank you for that.
I will use the RSI study in seeking out divergence as well, but like several other if not all applicable indicators I employ to exhibit the same divergence. I have began to use it in a similar matter to wmR% as far as study elevations vs pps historical support/resistance.
At this time there is no particular combination I favor over others and often I look for too perfect scenario amongst all indicators. There is no so called "primary technique".
I do like stochastics as well and dually employ them at different time frames. If both in oversold, I will feel better about a bottom type play at support an then look to histogram for a possible buy signal on an uptick w/ divergence in other studies making it more convincing to me. I prefer the stokes bottoms to not be in a longer rounding type condition but rather exhibiting a steeper/sharper approach.
I use the trendlines in stochastics as well for signals once breached.
LOL, I have no back pocket secrets and willing to share and exchange, accept criticism, and remain open minded towards new strategies as well.
The chart here offers a visual of all scenarios aforementioned:(at the time I termed it not so special due to lack of divergence, so example of expecting a perfect scenario is not necessary nor was applicable in this case)