I think it's going to be quite challenging, the layout of the FCU and the philosophy is very similar, but it's different how both 320 & 380 operate, in the a380, tcas maneuver is automatic by design, the 320 is manual.
When you land the 320, you have to lower the nose slowly by yourself after you touch down on main landing gear, but the 380 does that automatically.
Ptich attitude during engine out is 12.5 degrees for 320, but 380 is lower.
Flare height is different.
All of the mentioned above is just a tiny sliver of the differences between the two types.
That's why I think it's a bit challenging flying both types back to back since all individual aircraft systems are different with different limitations.
Regards,
An A320 co-pilot