Bruce,
I agree with Trevor & your "leanings" - cover lightly &
breathably everywhere (polypro tights!).
The difficulty is strange, sustained, and uneven
exposures that our bodies are not evolved to
handle. Light coverage everywhere helps diffuse
the negative impact of poorly distributed heating,
venting, and exposure by buffering loss-rates thus
allowing the body's inadequate regulatory activity
a little more time to react.
Insulation is hard to redistribute (hats & sleeves
excepted) during a ride but ventilation is not.
Think about it as venting the hot spots rather
than insulating the cold spots. Chose clothing
that has an abundance of velcro & zippered vents.
Pit or pec vents are great. They tend to balloon
your jersey or shell but they dump core heat +
moisture faster than anything else. I like baggy
shorts over my tights so the thigh-openings
catch&pump air up into the crotch. Also, I cut the
crotch & part of the pelvic panel from one pair of
my heavier tights. Leg warmers, as others have
said, are great for foot warmth in sub-freezing temps.
The head is different: you cannot go by "feel" so
much. I'm a *great* believer in a hat ALWAYS in
cool & cold riding - even if it's merely a light
cap with the bill spun to the back. When the head
is bare during exposed, fast-foward activity it
results in over production + shipment of heat to
the head - regardless of whether the rest of the
body needs or wants that heat. It really is
possible to "feel" warm all over but be pumping
huge amounts of heat through the head that lowers
your core temp. A balaclava in colder weather is a
beautiful thing - though I have trouble finding
ones I like the design of. Also, pumping excessive
heat through the head dries the sinuses thus
increasing susceptibility to common colds.
Hope that helps. Stay with the synthetics as they
throw-off the moisture best. I've a pile vest with
shell material on the front which has proven great
for a wide range of temps & conditions. I most
commonly wear that over a polypro, zippered
half-turtleneck long sleeve shirt.
I've never found a decent solution for the knees. Mine get cold long
before the feet and it's hard to insulate the knees without hampering
mobility. Consequently I've prematurely ground my knees. 🙁