A few notes I would like to add / clarify about squad sizes / tourney difficulty :
==== The battles are *exactly* the same for a base squad size of 100 or 1000.
--- Every province in round one starts at a percentage of your base squad size and remains at that level for each round of that specific province for the tourney, unless you take a squad upgrade in the middle of tourney.
--- Each province increases a bit in the percentage, until around 16 or so where is equals one full squad for each slot we use - and continues to increase at that same rate the more provinces you choose to battle.
-- The enemy scales at a fixed rate based on the round of the province.
-- Starting at about 85% and increasing each round by about 15%, until round 6 is roughly the enemy is roughly 160% our beginning size.
-- There are a few oddballs in that mix, province 5 and 7 come to mind for sure, where the starting size is much larger.
=== Loss rates are pretty much static across any squad size, not taking into account various wonders or battle boosters.
=== The difficulty isn't so much the battle .. but replacing the losses to continue gathering goodies in the rest of that week's tourney.
-- Far faster / less costly to replace 10% squad loss when your squad size is only 100 .. versus 1000.
== Squad size also is part of the catering equation in tourneys, but I don't know the specific math for that calculation.
Hope this helps folks make a better informed choice