Razorback DBC

My hand was: Void A Q J x A Q J x x x Q x x Partner dealt and opened 1S. I bid 2D. Partner bid 5D. I read partner for 18-20 dummy points for diamonds. Something like: A K Q xx 10 9 K x x x K x (or even A x) [With six good spades, I would have expected a 3S bid.] I bid 6D expecting the contract to depend on the heart finesse. Partner held: A K x x x x 10 9 K x x x x I was expecting a bit more. The opening lead was the club ace followed by a small heart. So six rolled. When we played it nobody else had bid six. Getting there should be straightforward. The bidding should go: 1S/2D/5C (splinter)/6D. The splinter bid shows good diamond support and a singleton or void in clubs. The splinter bid would let me show delayed spade support (if I had some) or cue bid the heart ace that would imply spade support and suggesting a spade slam.