Everyone should be in 4♠ but only half the field was.

South should open 1♦ and rebid 2♠ over 1♥ to show the 4-card Spade suit and their strength.

North then has a simple job to bid 4♠ .

Once you're in 4♠ the hand virtually plays itself so you make eleven tricks

The auction shown is for those playing weak NT and 4-card Majors. East should show their Suit rather than leap to NT themselves but when West shows a 15-16 point balanced hand then 3NT is the obvious bid,

Playing 5-card Majors and a weak NT the auction could go: 1♣ - 1♦  - 1NT - 3NT.

Playing a Strong NT the auction should be a simple 1NT - 3NT

If West plays 3NT a Club lead puts them under pressure. The best plan is win the ♣ A then play Hearts immediately. Fortune smiles when South has the ♥ A as if a Club continuation comes from South it gives the vital ninth trick away. A Diamond switch by South is also fatal for the defence.

When West gets back in they should finesse the diamonds into the South hand. As described above West has no need to fear South being on lead.