What's wrong with generating a couple of Engineers? If you are rushing a SV wouldn't using Engineers on Statue of Liberty and Hubble Space Telescope still help with a SV?
Well, you only have 1 scale for G Engineers, Scientists and Merchants. I don't remember the exact scale but it is something like 100, 200, 400, 800, 1600 GPPs, ect.
Now if your going to have 3100 points of "spent" GPP by a certain point in the game then you can only have 5 great persons. That's it (within that timeframe).
If your first 3 are Great Scientists, then you have 2 Great Engineers, and your last one is a Great Scientist then you come out of it with 3 Scientists and 2 rushed wonders.
If all 5 are Great Scientists then you end up with 5 Scientists.
The point is that the GP you get are pretty fixed within a certain time frame, you can have 3 Scientists, 2 Engineers, 0 Merchants, or you can have 5 Scientists, or another combination.
The real point is that people generally view the Science Victory Condition as a race, more Scientists means you go faster, detouring to get an Engineer slows you down, and don't even think about getting no Great Merchant! We raised you better then that, Sonny
However this is often not the Olympics and if you want to detour and get an Engineer for a wonder then go ahead

Efficiency isn't the only goal
