This does raise a point though:
I am trying to build my lances in such a way that in their respective eras, the mechs/variants actually have been available to whatever unit that fields them. If it's extinct or only available to ComStar, I usually tend to not use them (unless in very, very few occasions, like a DC lance with a Royal Regiment Version of the Shadowhawk that I flimsily excuse as a one-off during Operation Rosebud).
In some minor cases, I put a mech or variant in a unit that was readily availabe to other factions and excuse it via salvage.
So it's not like I am 100% strict on what to put where, I just try to avoid contradicting MUL as best as I can.
But of course, putting Clan Mechs in IS lances before the Clan Invasion is a no-go....
How do you do it? And how do you go about fielding Clan units in IS lances? Are Clan units just fair game as long as the MUL says that faction has access to it, do you take into account the unit that fields them. Ie: a unit that spent its sweet time dicking around far away from anything Clan Invasion is SOOL, while some frontline Operation Bulldog veteran unit just swims in sweet sweet Clan-brand bullshit weapons?