What changes did you make to the rules for such a large game???
In brief:
1. Units organised into 'companies' with 3 identical units + leader (sergeant) on one unit card.
2. Suppressions limited to 6 per unit. When they got to 6, unit had to test for Pinning as if it had more suppressions than models. This kept down the number of counters in circulation.
3. Didn't use the -1 to hit for suppressions unless the unit had 6. This speeded up dice rolling.
4. We used a simple combat table to make sure that any melees were over after 1 round of fighting.
Those were the main changes - just a few experiments to streamline things, and on the whole they worked.