As respondent,How will you try slam?
My idea is jump 4th suiter 4c=7keys three-suited-ask,It's reasonable and saving space.
After analysis of these sort of hands, You will find you have 3 suiters in both hands,and It’s not surely the best with 4-4 fitting suiter as trump.for example
You can make 6d/s,but 6h
You can make 6h,but 6d/s.
AKQ in 3 suiters you have are all important,how do you know how many of them you have in both hands?
Maybe my idea is one of plans:
jump 4th suiter=7 keys in 3 suiters asking
answer:
plus 1=2 keys at most without intresting in slam.
plus 2=3/6keys or 1key with 3 queens
plus 3=4/7keys or 2keys with 3 queens
plus 4=5 keys
responder can go on asking queen with close 4th suiter or nt
and answer:
plus 1=0/3queen.
plus 2=1 queen in lower suiter without queen in 4-4 fitting suiter
plus 3=1 queen in higher suiter without queen in 4-4 fitting suiter
plus 4=2queens without queen in 4-4 fitting suiter
plus 5=1queen in 4-4 fitting suiter
All is my fantasy.
and the highest asking-bidding is 5c:
example 1s-2h-3d-5c
the lowest asking-bidding is 3s:
example 1c-1h-2d-3s
or you can use 2s=asking when responder passed
example
1c-1d-1h-2s
2s=asking if it comes from passed hand