Ok, but when I played in Tigranes TGW-Div PBEM, I played Russia then France. These were consecutive tribes and instead of saving I would just hit continue. Fast workers were not noticable in that game. And it was a very long game.
OKay... you don't trust me.
So, just take 5 min and open Civ III Conquest.
Set a Pebm game, put 2 human players.
With worker, mine... on a plain, it will take 6 turns (for a non industrious civ).
Don't settle nor choose science... here we just verify that workers do work twice faster as expected.
End turn, clic continue.
2d civ... do the same.... end turn, clic continue
You now open, 2d turn of civ 1, if you clic on your worker, a message will say that 4 turns are remaining to mine.... As it should be 5.
End turn, play 2d civ,
3rd turn of 1st civ... clic on worker...
2 turns remaining...
4th turn... mine is complete; and the worker can begin a new task.
Result... 3 turn to mine instead of 6
......
So... i think you should save game between you 2 civ... or that we wait for your partner to come back.
But the best would have been to not set 2 civ of a team simultaneous (and there is only 1 team on that position)
GPS to Eclipse