I can give you some pointers on playing a scientific civ at Deity - I have played the Russians.
I found the free tech with each new age invaluable for keeping up in the tech race.
Sometimes I past into the next age before I got my free tech - then I choose the tech to research that I least wanted (either one others already had or the one that takes the least turns to research) then I got one of the other 2 entry level techs as my freebee - then I changed to the tech that I realy wanted to research.
I have some theories why sometimes I got my free tech before or after I get to choose a new tech but have not tested them yet.
- I believe either how you got the tech may determine timing or if you are reseaching a dead end tech or not.
1) if you are researching a dead end tech and you go up because of a tech trade you get no choice.
2) the timing of recieving your free tech depends on if you reseached it or traded it.
As a Sci. Civ with free techs, trading techs, building the ToE you should be able to maintain tech parity - this makes a Diplomatic or Spaceship win possible.