@Momonar
Short answer: yes on the WS bldg sizes by level (they're listed as 2x2, 3x6, etc); here's a
link to the workshop table on the Wiki. The link drops you into the Elves WS; scroll down if you need to see the human one instead. Also, sometimes these tables are collapsed; you'll see 'expand' on the top right corner of the table to click if needed.
As to the situation of fewer WS needed, here's what's going on in my Ch17 city (I should say the game considers me 'in' Ch18 because I completed the first tech for higher rewards in the Winter event bldgs):
I have event bldgs for pop (so zero houses placed) and regular goods (so no regular factories, just sentient ones) which means I've been at the max (without EE spells) of 170% culture for months if not a year now. I recently used a boatload of EE spells for mana from my lvl 17 Dragon Abbey (and will do so again in the next couple days) to upgrade some sentient factories to max lvl, so I'm at 230% culture right now. It's been above 200% since the last FA consistently. My PT is lvl 8 and I have 2 Ch17 lvl Magic WS (that I'll wait to win more in the Spire at Ch18 to replace). I'm not a rabid tourney player, but increased to 8100pts/wk (6 rounds of 30 provinces) with this cycle (started with marble, so this is the 4th week). I'm 100% combat in the Spire (complete it to the top weekly) and ~90% combat in tourneys. With my hoarding nature, I start hyperventilating if my squad sizes drop below the >999 squads as shown in browser and train furiously to get it over that again, but that has not happened in this cycle so far. Frogs may do it when I do this week's tourney, but that won't be until Fri/Sat. At this point, I'm using PoP spells on the WS's 2-3x's/wk, but I have 4200+ of those in stock, so that can increase with no significant issues if needed. I also have supply instants that all added together = 13,280% (in case you didn't believe I was a real hoarder, lol!) 'just in case'. I find if I need to cater more in tourneys (usually due to rl and not enough time to manually fight 'iffy' enemy lineups), or am having a panic attack over less than 999 squads and feed the Brown Bear/use time boosts (haven't fed the bear in months!) that's when I use the supply instants. Also, I absolutely despise the
gouger wholesaler; I'll push through troops with time instants to burn off any excess instead, but prefer to just have less supply production since I have plenty of 'back-up' (
at myself) if needed.