Here's a few hints (this is my specialty and core interest after a career as MM /derivs sales spanning 25 yrs)...
Index MMs are reflexive- when they are strained, you will see evidence of it in the pricing.
Short vol strats abound- it's not true that index MMs are all short-put, long-call. Not true at all.
But you can still count on the fact that traditional / vanilla hedging is *mostly* done in the quarterly month and end-of-year expiries. That means you *will* have more traditional positioning existing in the third Friday AM maturity for any quarterly month- as well as any end-of-(quarterly)-month tenor.
In between- the M, W, Fs are dominated by vol sellers or event hedgers- rarely do white shoe types hedge real AUM on a non-standard tenor.
You'll of course have some volatility shops playing the term structure, but this series of rules is enough to help anyone make sense of *when* to rely on a traditional/standard measure of GEX (like a quarterly month, wk2 through EOM), and when to assume the real deal is much flatter / wider (all the rest of the time).
