If people funnel most of their attention into going over the 10+/10 limit, could you tell roughly what it'd look like as a bonus?
A little bit of quick spreadsheet work tells me...
The current sweet spot is 2% of our force devoted to combat units which require crafted weapons, 10% crafters, 50% unassigned (meaning gatherers), 38% fighters which do not require crafting support.
That starts from our current assignments as a base, where we have a lot of non-craft fighting skeletons already. 29% of our existing forces are stone skirmishers, punchers, or scavengers.
Each 1% of our force devoted to fighting skeletons that require crafted weapons accounts for an effective 31% of our army: 1% fighters, 5% crafters to supply fighters, 25% gatherers to supply the crafters. Thus, our current hard cap on armed fighting skeletons is 3% of forces; that ties up 93% of the entire horde, leaving 7% for miscellaneous non-supply-consuming skeletons.
Our soft cap is 2%, because we've already got 29% of the horde allocated to non-supply fighting skellies. Getting supplied skellies up to 3% would mean converting 22% of the horde from fighters to non-combatants, and our best supplied fighters, the primitive spear-fighters, are good, but not 22 times as good as the best trainable non-supply fighting skellies, the rock skirmishers. Scavengers are (usually) stronger than rockers, but have an element of chance, no ranged ability, and we can't train more.
So, since we've already got 1% of skellies assigned to be stone knife assassins, and 1% assigned to spear carrying, we shouldn't increase either of those forces much higher without decreasing the other, or we'll be unable to support their full numbers.
For crafting, we want to get to 10% crafting skellies, and we do not want to exceed 11% crafting skellies, or we outrun our gatherers and waste capacity.
For fighting skellies, to maximize combat power, we want to leave our current stone blade assassin and spearman levels where they are, or possibly reduce assassins to 0% and increase spears to 2%, then try to convert another 9% of the horde to rock skirmishers.
Alternate plan: Reduce assassins to 0%, leave spears at 1%, increase rock skirmishers by 40%. I don't think we've got the action economy to achieve that before the fight starts, though; even 9% will be tough, so might as well keep the assassins.
Also, this would be an excellent turn for one of our leaders to make a defense plan.