Mass Combat Rules

What is the proper way to apply damage to a PC per the mass combat pdf on the site?

They act independantly but how much damage should be applied to the PC if the PC is attached to a unit?

For example, 2 PCs are leading 30 Soldiers to wade in and slaughter 40 Picts. The majority of Picts will attack the soldier counters, but they aren't going to just be ignoring the PCs lopping their heads off. Should a % of damage done to the unit be applied to the PCs or should I randomly decide X picts take swings at them? ( want to keep this mass combat and not individual.)