"Badger_South" wrote:

In that case of only wearing shorts with 'fake chamois', it probably
doesn't matter if you're wearing underwear or not. That pad is just for
padding and performs little if any of the original friction reducing
function. Riding most distances under 25 miles will not give you saddle
sores unless you forget basic hygiene.

Disagree. You shouldn't wear underwear when wearing any padded shorts.

And having used both traditional chamois and what you call "fake," I'll take
the "fake" stuff any day. After a few washings the genuine chamois would dry
out, become stiff, and crack. The imitation chamois is more comfortable and
lasts much longer. It is far superior, just as modern jersey fabrics are
superior to wool.

As to the OPs question about tights, you should wear padded cycling shorts
(and nothing else) under them.

Art Harris