After trial and error, and helpful hints from this forum, I have now settled on a combo of Bag Balm (apply it directly to me, not the shorts) and pure corn starch (helps keep me drier much longer than powder or talc). Some of the other chamois cream-type products I tried did not wash out of my shorts but no problems with the Bag Balm.

For saddle sores, straight aloe vera and/or a lanolin based cream seem to provide the quickest cure.