The all-glass Cirrus has a set of emergency instruments - a card
compass, an ASI, altimeter, and AI. It also has dual 430's. If the
PFD fails, the factory recommends you couple up the A/P to the 430 and
not try to hand-fly it. I would almost certainly screw up trying to do
that.

I don't see how. Assuming your 430s have a flight plan and you're following
it, all you've got to do is engage GPSS and ALT. Or GPSS and VS and then
dial in the vertical speed you want on the autopilot.

On the other hand, I have no doubt I could fly a good GPS
approach simply using the 430 map and the available panel. Partial
panel with an AI? Luxury!