Thanks all.
Most RKCB references I've found have 5NT denying a king, but it makes sense to save space by jumping to 6 trumps without a king, using 5NT to show some sort of stronger hand (either the K of hearts as P_Marlowe says, or more general as per nullve).
Fluffy, on 2016-October-25, 09:24, said:
The wrong hand is taking control in both of your biddings.
I can't see how to get to a point North would be able to + know to do so.
Fluffy, on 2016-October-25, 09:24, said:
On first one you also skip the 4-level for no reason.
Mainly because playing first round controls, I couldn't see how adding 4
♣ - 4
♠ could help anyone - if anything, it's going to make partner more likely to think I'm missing an ace.
I guess if you allow second round controls, 4
♣ - 4
♥ would give me the heart king info slightly earlier, if that helps (such as partner being able to show the Q of hearts during the trump queen ask as Cyberyeti suggests).