That's a creative thought!
These are the sciences we are talking about:
Astronavigation (80) (10 green)
Coinage (90) (10 green)
Empiricism (60) (10 green) (10 to Medicine)
Written Record (60) (5 green + 5-10 optional*)
Calendar (180) (10 green)
Medicine (140) (10 green) (20 to Anatomy)
Engineering (160) (5 green)
Cartography (160) (10 green)
(* I'm counting 5 or 10 depending on the possible change of Written Record which raises the optional credits by five)
(
http://www.civproject.net/forum/viewtopic.php?p=3641#3641)
When you want to add this ability it will be because of Paul's opinion.
that means, you already have at least three of the lowranges otherwise you could take two 0-100 sciences
That makes the following calculation:
(25-30 green credits and a 100 discount to the midranges)
(Not couting an optional 5-10 green credits for Written Record)
Calendar (50-55) (10 green)
Medicine (10-15) (10 green) (20 to Anatomy)
Engineering (30-35) (5 green)
Cartography (30-35) (10 green)
If you count Medicine with that, it makes this calculation:
(35-40 green credits and a 100 discount to the midranges)
(Not couting an optional 5-10 green credits for Written Record)
Calendar (40-45) (10 green)
Engineering (20-25) (5 green)
Cartography (20-25) (10 green)
If you regard you already have all four cheap sciences
it becomes this:
(35 green credits and a 100 discount to the midranges)
(Not couting an optional 5-10 green credits for Written Record)
Calendar (45) (10 green)
Engineering (25) (5 green)
Cartography (25) (10 green)
If you regard you already have all four cheap sciences
AND medicine: it becomes this:
(45 green credits and a 100 discount to the midranges)
(Not couting an optional 5-10 green credits for Written Record)
Calendar (35) (10 green)
Engineering (15) (5 green)
Cartography (15) (10 green)
That also gives away the three sciences left almost for free.
If we choose for this option it will be close to our first proposal (two 0-100's or one 100-200) which gerart rejected.
Besides the card might be close to Library this way.
(which gives 40 credits to any card)
I don't think this is the solution, but it might be a step to one.