I am working on Wigram Grouping a lot at the moment, with a a friend of mine in the UK who runs a Regimental training team.

The whole point of Wigram's idea was,

a.) Use with almost any amount of troops found in a platoon, so 18-40.
b.) It used exactly the same method of Manoeuvre as was taught to sections in the 1940/1 "Battlecraft" manual, but applied to the platoon. Wigram had never taught 'section manoeuvre' and his original manual discussed the "section IN the Attack", NOT, the "Section Attack."
c.) The Group contained three complementary elements of, "Reconnaissance" - The Rifle Group, "Suppression-Strike" - the Brens, and "HE-Projection" - The 2-inch mortar.

So a 30 man platoon could be,

Recce Group, = 3 x 5 man teams with IWs and TIWS
Strike Group = 2 x 5 man teams - each team with GPMG
STA team = 1 x 5 man team with 60mm light Mortar (M6-640) and 1 x 8.6mm rifle.