One thing I figiured out last fall, you really cannot get overly wet wearing spandex , not my Aerotech bibs and lg long sleeve thermal jersey anyway, with a target duo dry long sleeve shirt as a base layer the inner shirt never got any wetter than riding on a day when it was not raining.
that day was 37f too, and the first day I set OUT into the rain :-), my feet got warmer once my shoes filled with water :-). I have never owned a rain shell and so far have no plans of buying one.
I had one saddle on my journey from 280lbs to 183 today that only worked for 30 days, it was magic on day one, agony on day 30. One benefit of performance bike, just take it back :-).
16f was my lower temp limit this winter, I was unwilling to invest $ into clothes for colder that would only fit for a month or so.