I don't realy know, but i usualy stop between province 30 and 35 with my main city (+ sometimes few extra by negotiating for event quests), this way my time instant stock is slowly growing. I could probably go few provinces further each tournament without draining my time instants stock and without using additional booster buildings (i'm using 4+2+2 combo for two Spires & two tournaments).
But if i wanted to, i could go all the way to the end by using more time instants & booster buildings temporary (In unsustainable amounts, i have large enough stock for that).
My beta city has probably lower capacity since it has never been optimized for tournaments and Simia 12 , Martial Monastery 16 and Dragon Abbey 6 are the only military wonders i have there.
So i don't do more than 15 provinces and 5 rounds on beta (16h cooldown).
And often i forget to do some rounds on beta (side effect of having 0 cooldown in my main city), so sometimes only 2 or 3 rounds when i realize on friday that i had done only 1 round so far.
But i have never tested my true abilities there. I'm using the same 4+2+2 combo, but only for 2 rounds of Spire, so usualy only 1 or 2 rounds of tournaments are affected by them, the rest runs only on Fire Phoenix.
Golden Abyss 30 for max population
Needles 26 for Archer bonus & Barracks training speed
Monastery 30 for max. HP bonus (culture bonus is a good side effect).
Watchtower Ruins 21 for more culture (and less need for cultural building giving 0 ranking points).
Thrones 23 for more ranking points (some culture as a side effect).
Mountain Halls 30 for max population.
Prosperity Towers 16 for more tools and better Power of Provision spell effect (97k/3h and 349k/3h is a big difference).
Heroes' Forge 11 for Heavy Melee bonus.
Shrooms 17 for bigger effect of Armories on training size (i have 16 armories to have training queue over 20h to be able to use 20h time instants).
Flying Academy 26 to increase speed of Mercenary camp
Maze of Dark Matter 31 mainly for the 2% mana decay (once upon a time deleted on 11 then rebuilt to keep up with milions of mana requirements)
Dragon Abbey 26 for Mage damage and fast mana from spells when needed
Temple of the Toads 18 to increase the heave ranged dmg.
Elvenar Trade Center 35 for Magical manufacturing spell boost + some extra seeds
Sunset Towers 22 for lowering the seed decay (3,8% currently)
Pyramid of Purification 19 originaly mainly for some extra expired(sentient) goods + some extra units. I could live without this one, but with so many armories the bonus production from orcs can help when trader is switched to unurium.
Time Warp 30 for 0 cooldown when Polar Bear is fed.
Simia 35 for 2% expired goods decay and 46% extra unit production (basicaly one more pernament brown bear without feeding)
Thermal Springs 35 for maxing population on residences (i don't use pop/cult buildings with exception of some evos and sets giving other more useful bonuses).
Some wonders have quite a big difference in levels, mainly due to prioritizing one over another to max one as soon as possible.