Ok, I would go back to a 12.30 nap just until you can get some decent nights so that you can rule out whether she is OT from the short nights. It IMO will not help keeping the morning long if she's OT from a short night yk. So I would do this:
WU: 6am
Nap: 12.30
BT: 7pm (13h after WU)
Please remind me, do you cap at 1.5h or is that her natural nap cycle?
Once you feel her sleep is back on track, and you want to try for a later WU, then you could consider pushing out to 12,45pm holding for one week and assess the effect. That said a 11h night and 1.5 DTS is not bad at all at this age IMO.
What do you think?
Hena