Korea estimate, using a simple 4-city example, all on hills (no windmills) next to mountains
Expos (3)
Specialist buildings: Uni, School, Lab, Market, Bank, Workshop, and 1 of Stock Exchange/Factory (i.e. 7 out of 8 specialist buildings) = 9 specialists = 18 science from UA per expo
Modifiers at 150% (Uni w/ Rationalism policy, Observatory, Lab) --> 45 science per expo
With 3 expos, that's 135 science from UA
Terrain
Estimate 1 GS and 2 Prophets planted = 6 base science
Personally, I try to plant the prophets in expos and the GS in capital, which gives different modifiers.
Prophets (2 x 2 x 150%) + GS (1 x 2 x 200%) = 10 + 6 = 16 science from UA
Capital
If 8/8 specialist buildings and 2/3 guilds (Writers, Artist), that's 15 specialist slots = 30 base science x 200% modifier = 90 science from UA
Total in this 4-city example with 7/8 specialist buildings in expos, 2/3 guilds, and 3 great people planted is 241 science from UA
Ex. 2: 4 cities by mountains, no Windmills. 8/8 specialist buildings in expos, 3/3 guilds, still 3 great people planted but all in capital:
Expos - 11 specialists/22 base science x 150% = 55 per expo x 3 = 165
Terrain - 3 x 2 x 200% = 18
Capital 17 specialists = 34 base science x 200% = 102
285 science from UA
Ex. 3: exact same as first example, but with a 4th expo for 5 cities total: 241 (total from first example) + 45 (4th expo) = 286
Ex. 4: exact same as #2, but with a 4th expo for 5 cities total: 285 + 55 = 340 science from UA
Ex. 5-7
Wide empire with 7, 9, or 11 cities
Average of 6 specialist buildings/8 specialist slots per expo = 16 base science per expo
Estimate 50% of expos have Observatories, therefore modifier average is 125%. 16 x 125% = 36 science from UA per expo
Terrain. Let's go with 3 great people and 16 total science.
Capital: Go with the #s from first example = 90 science from UA
7 cities = 90 + 16 + (6 x 36) = 106 + 216 = 322
9 cities = add 72 to above = 394
11 cities = add 72 to above = 466
I realize in spots I just wrote the modifier (ex. 200%) instead of the actual calculation # (ex. 300%); hopefully people understand what I mean.