The opener had 18hcp (within which some players would have opened 1NT). The Michael user must have some hcp, 10 for example, so that he could buy a safer contract (spades would be on 2-level and minors would be on 3-level). Assuming east had 7hcp, he dare bid spades when the bidding level had jumped to 4. So how could north have?His hand was most probably weak(5-hcp) but distributed in some degree (at least you had gotten 5+support in trumps by preemptive 4H). You were likely to have 2tricks on minors, one in KQ and one in AK (be careful of the meaning of Michael). But you had 1trick at most on hearts because they had a singleton at least and you needed HA on your p (if that your p had no honor cards in spades). 4S would much probably be made. So how about 5H?Your hand was strong enough to hold 3suits except spades. You would be apt to lose 1 on diamonds, 2 on spades and 1(ace) on hearts. However, we still have no idea of the distribution of clubs but it would led to the result at a key point, maybe 4S= or 4S-1 and 5Hx-2 or 5Hx-3. Hope you were lucky to have a satisfied result.