The bidding goes:
1♥ - 2♦ - 3♦* - pass
3♦ means 9-12 HCP, 4+♥ and some shortness (you know opps that far, that you can freely assume it is not ♦ shortness).
3♥* - pass - 3NT* - pass
3♥ is question which shortness, 3NT is spade singleton.
You need ♥Kxxx and ♣KQx or ♥Kxxxx and ♣KJx for reasonable slam.
I tried it.
4♦* - pass - 4♠* - pass
5♦* - pass - 5♥ - pass
6♥ - all
4♦ (diamond cuebid, denying club cuebid; I desperately need the club king, partner will bid 4♥ without it - according to our agreements).
4♠ is allum, 5♦ is 1 of five with queen or 3 or 4, 5♥ is final contract against minimum, 6♥ shows 3 without side values.
At the table partner was maximum, but has all the bad points he could have:
♠Q ♥KQJxx ♦Jxx ♣Kxxx
So I made only five.
Was it reasonable slam?

Help
