I'm using Compact double cranks, 48 or 50/34. I also wax
my chains and don't oil them. The inward movement of the
front derailleur is adjusted to that it either grazes or
just misses the inner cage in the small/small
combination. Derailleurs are Campy 10 but also used
Shimano DA, 105 and XTR 900.
I noticed that the chains dropped more freqently when the
chain was approaching time to rewax. I also read here that
the big ring needed to have any burrs smoothed. My
chainrings are almost new.
I very lightly greased the teeth of the big ring and,
voila, the chain does not miss the small ring on the
downshift. The grease picks up a little dirt but nothing
like an oiled chain.
The tandem, also a compact double, 50/34 x 12/34 has an
N'gear Jump Stop. That's the best way to go.