The most popular slam bidding enquiries are based either on 4C [Gerber] or 4NT [Blackwood et al].  They each have their advocates.  Some partnerships play both.  The trouble with 4C is that it removes what could otherwise be a useful natural bid.  The trouble with 4NT is that there can be too little space to explore minor-suit slams safely.  An idea, new to me, has the attraction that it allows equal space for exploration, whatever the agreed suit.  The enquiry begins with a bid at the four level exactly one step above the trump suit.  You may lose a rarely used Cue Bid, but gain considerable space.
Such a sequence as 1D  -  3D  -  4H? would be a control enquiry assuming Diamonds already agreed as trumps.  A sequence such as:  1S  -  2H  -  3C may well leave responder wishing to explore a slam in one of the three suits already mentioned, but there is no easy way of nominating that suit without running the risk of partner passing.  The solution is simple, if responder bids 4D, Clubs are the agreed suit.  To set Hearts responder bids 4S; to agree Spades the bid would be 4NT.  In each case, at the four level, one step above the proposed trump suit.  Responses to such enquiries remain the same in concept as before: step responses.  Those along the Roman Key Card lines work well:
       1 step:  0 or 3 key cards;
       2 steps: 1 or 4 key cards
       3 steps: 2 key cards, without the Q of trumps (nor a 10+-card fit);
       4 steps: 2 key cards, with Q, or revealing a 10+ card fit.

Having learned that all 5 key cards are present, and that the agreed trump suit is solid, one may wish to enquire about the remaining three kings, with a Grand Slam in mind.
This enquiry is launched by repeating the 4-level asking suit, but at the 5 level. For example:
 1D  -  3D  -  4H?  -  5D (4 steps)  -  5H? ( for remaining kings).  The style here too, is similar to standard methods.  Responder bids the cheapest king held.  Note this is NOT necessarily the lowest ranking, as happens when 5NT is the enquiring bid.  So after the above sequence:
       5S would show the KS;
       5NT would show the KH; (NTs are used to show the king of the asking suit)
       6C would show the KC, but no others;
       6D would show no kings outside trumps.
       7D would show all 3 missing kings.  Enquirer may possibly convert to 7NT.

With two of the outstanding kings responder just bids the cheaper, as asked.  Should the enquirer wish to seek another potential king holding, the suit concerned is bid, again NT representing the asking suit.  The positive reply is to bid the Grand Slam, negative the Small Slam.  Thus a complete sequence could be:
1C  -  3C  -  4D?  -  4S (one key card)  -  5D?  -  5S(KS)  -  5NT(KD?)  -  7C(yes)

        S A Q x x           S K x
        H x                     H A x x
        D A Q x             D K x x
        C A K Q x x      C x x x x x

A standard sequence could begin:

1C  -  3C  - 4NT?  -  5D(one)  -  5NT?  -  6D(KD: lower king)  or 6H(two kings).

You are already above 6C and there is no room to identify the king of spades.  6NT is not a good contract if partner holds KH instead of KS.
Of course there are those who would say the Gerber solves such problems, but it creates others.  4D as the enquiry gives you plenty of space for a Club Slam.  If you really like Gerber, then it now can be reserved strictly for seeking NT slam contracts.