I played Friday in a two session event in Washington. This was a two session pairs game, with an upper limit of, I think, 10,000 masterpoints for entry. I would qualify to play if the limit were much much lower. We were the defense on the following hand, and I will say a few words about that later. But for now, I want to consider declarer's options. The hands are rotated so that S is declarer.
1♠ shows at most 4 spades
Lho inquired about the alert of the 1♠, you explain that it shows a holding of at most four spades. Your partner expands on this, saying that it could be as few as 0 or as many as 4. Lho consults your cc, presumably noting that you are playing Flannery, and so from your minimum rebid of 1NT, along with your non-Flannery opening, he can infer that you do not have four spades. After a little thought, he leads the ♣ 3. Your right hand opponent plays the ♣J, then the ♣Q, then the ♣9. On tricks 3 and 4, lho takes his ♣A and ♣K. On the last club, rho has discarded the ♠3. At tricks 3 and 4 you have discarded the ♥6 (four heart tricks are plenty if you can get them), and the ♦7. Lho now plays the ♠2.
How do you see this going? It is true that at many tables the auction will begin 1♥-1NT(forcing) and N will declare, but I doubt this is relevant. You need to take nine tricks here, regardless of what happens at other tables.
If it matters, I doubt that it does, the opponents are playing standard leads and carding. But I suggest you do not make too much out of the spade 3 discard. Putting this another way, if you play low from the board and honor will appear on you right.
At the table, I was on lead and we did take the first four clubs. The discards were not exactly as I have described, but I think they should have been so I revised tampered with the truth a bit, hoping to make it more interesting.
You have 8 tricks on top, the defense has taken 4, so the position is tight. There are options but, so far, I have not seen an optimal line that will work against any lie of the cards. I think it doesn't exist.