I like my Diva Cup - but don't love it as much as the old latex one that the dog ate There is a bit of a learning curve, so if you're going to try one, get it now for your next period, not for the first time on your big ride.

You didn't say why you can't wear tampons. If it's a history of TSS, they recommend not using a Diva Cup either, even though there's never been a known case associated with the cup.

If it's just the string on the tampon that's an issue, you can tuck that up inside.

If you're not a heavy bleeder and you have a black saddle, chamois are made to absorb a lot.

If there's some reason you must wear a pad, I'd guess you'd want to use the narrowest, lowest profile one you can buy, no "wings," and the strongest adhesive, and stick it tight to a pair of shorts with a very low profile chamois, then use lots of lube. If it sticks tight it probably won't be too much different from some of those bulky chamois.