Again, it depends.. your culture bonus effects your workshops.. the more, and the greater the culture, the more tools you produce.. as this is product which is capped by your main hall, you may find that you have too much.. but you can use it to produce troops and orcs and spend it in the wholesalers.. so excess supplies which is what your culture bonus really does may not be a problem... I like to have 10 workshops.. that's a hangover from quests, and FA"s.. when I run low, I use the instants I've won in tournament, and event, and generally... I am happy with a 150% culture.. I tend to Fragment ensorcelled endowments, as being the least useful.. I can envisage a city with few workshops, and high culture but I would say it suits a player who is logging in at least once every 24 hrs.. and of course, that leaves space for more AW's and special cultural buildings, or more manufactories..