2/1 base.
1N=good 14-17
2♠=weaker of two ways to show 6+ spades
Lebensohl in play, so some obvious responder options are:
2N relay/3N=to play with ♠ stopper
3♦=GF 5+♦. 4N over 4♦ rebid would be 0314 RKC.
4N=quant slam invite. After 4N, if accepting opener will show aces using Blackwood responses, after which you can offer diamond slam w/ 6♦.
Benefits include:
Plus... it's free!