MAC is the best concept and also the best way of catering for the many people who want lots of marchers.
But for non MAC sets.

12 figure sprue.

A selfish choice would be
3 standing firing.
3 loading.
3 advancing.
1 officer.
2 marching.

but a fairer arrangement might be

3 standing firing.
3 advancing.
3 marching.
1 officer.
2 Whatever.( I realise this does not discount the possibility of another marcher.)

8 figure sprue.

2 standing firing.
2 advancing.
2 marching.
1 officer.
1 whatever.

Non MAC sets do, I think, need to include officers.