The Hawker 800 aircraft I flew could be switched from dual cue to single cue with a button in the cockpit on the fly.
slight thread drift continued...
When I went to FlightSafety for Hawker 800XP training I discovered the same thing. All of my previous jet experience was on "steam gauges" so the Honeywell glass setup was entirely new to me. I'd heard all the nonsense regarding the difficulty of the transition to glass so when I climbed in for sim session one and saw those two needles on the EADI screen instead of a proper V bar...
After "faking" my way through a takeoff and departure procedure looking "through" the FD cues to the raw data I decided to try following the cues. It reminded me of the GS and CDI needles on the old 172s I'd trained on years before and I eventually started to get the hang of it even though I was decidedly uncomfortable. When I mentioned this to the sim instructor, he laughed and directed my attention to the switch on the panel to my left. What a relief!
Veering momentarily back on topic...
I did have an exciting moment once in that Hawker when the EADI on my side went dark while flying a DP. I looked at the stby ADI and saw the attitude was still the same (10 deg NU and 25 deg bank) and that the co-pilot EADI looked normal so I asked the other guy if he wouldn't mind flying rather than test my skills on the little stby AI. We switched roles long enough to reach a safe altitude and reset the EFIS power. We never did figure out why this happened but figured that those little stby instruments might yet come in handy one day. I've never yet been required to demonstrate competency at flying an IAP using stby instruments only during any training/checking event. The way I see it, a real emergency is no time to find out you're not up to the task.
Just include flying solely by reference to the stby instruments in recurrent!
And BTW it's not that big a deal once you've tried it a couple of times.