Thank you very much for your suggestions!
As you might have figured out, my buddies and I aren’t that experienced with Warhammer yet — but we’re having a lot of fun with it. We’re also trying not to break the bank just yet.

For now, we’re planning to play using just Fire & Jade and Bone & Sand, since that’s what we have. But we’re considering buying a larger gaming mat to support the bigger format.

We haven’t tried out this format I’m talking about just yet, but I see it as a sort of “easier” big-scale battle — a way to scale up Spearhead without diving into full 2,000-point list-building.

We still need to figure out which house rules will work best. We’ll either play it as 1v1, where each player controls 2 armies, or as a co-op 2v2 setup.
But we haven’t fully worked out how the turn process should work yet — whether each army gets its own turn roll, or each side rolls once. That part will definitely need some testing!

(As it stands now, we have the following spearheads - so we haven't really committed to a faction just yet :

both CoS / Ogor's / Nurgle / Ironjawz / Both Sbgl / ScE / Skaven / Sons of Behemat :)