BALANCING SEAT AUCTIONS after 1-suit pass pass

The auction goes:  1suit  PASS  PASS  ??

To you. The Notrump Structure Changes:

1NT = 11-15
X  followed by cheapest NT = 16-18
2NT = 19-21
3NT = gambling - long solid minor with stopper in their bid suit

OVERCALL   7-16 HCP, 4+ suit
X followed by minimum response, and simple new suit rebid = 18-19 HCP, 5+ suit
X followed by jump rebid = 20-22, 4+ primary support for advancer's suit
X followed by cue-bid = GAME FORCE, 23+ "playing points"

SO ... the bidding goes:

1S   P   P   ?     x   Jx   AKxxx   A1087x

Just overcall two diamonds (intending to compete to 4 clubs if necessary)

1S   P         P   2D
X     2S*      P   4S**
P     5C***   P   5D or pass****

Advancer's hand:   xxx  A9x   Jxx   KQJx

*  10+ HCP with xxx or better

** game-force, slam invite with stiff or void of spades

***  concentration of values

**** enough is enough - there might be two hearts and a spade lose