I do as Andy suggests and keep enough chain that a clumsy shift to big-big isn't a big deal. And I have no issues with excess chain slack in teh small-small combo. First, on my ramped and pinned 9-speed cranksets, I cannot even use that gear because the middle chainring will pick up the chain. On my 7-speeds and all my setups in the past, small-small, even with so much chain slack it was nearly dragging on the chainstay, mattered little. (I only use the smallest available cog and inner ring when tough hills lever out temporarily, rather than doing a pair of double shifts.)

So,in short, I have exceeded capacity many times with no issues. But I have walked home from undersized chains after a big-big shift.

The cage folding back on itself - a new, interesting noise but the odds are everything will work just fine. (Can be hard on the chainstay paint if you ease up on pedaling over rough roads.)

Ben