Rasher, your computer is very similar to mine (AMD dual core @ 1.8, NVidea 8600GT, 1Gb Ram) so it should run fine without many problems once you get out of the port area. If it is still too slow in port, try using the GWX Lite Harbor mod to decrease the air and sea traffic.
I found the adjustments for crew fatigue. I will assume you are using SH3 Commander, which makes making the adjustments very easy. Here is the procedure: Navigate to your SH3 Commander\Cfg folder and look for the Crew fatigue models.cfg file and open it with a text editor. Follow the instructions at the top of the file for adding your own fatigue model.
As for specific settings, start out with my settings, which follow. Mine are based on the Rub model instead of the Rub X 1 TC model, but you can try either one. Just copy either Rub or Rub X 1 TC as described at the top of the Crew fatigue models.cfg file and paste it to the end of the file. Number the new model with the last number of the model just above plus 1 and add a new description after Desc= . Finally, copy the following lines over the matching lines of the just copied model:
Code:
CREW_0|FatigueMax=0.75
CREW_0|FatigueStep=0.0175 ;was .02
CREW_1|FatigueMax=0.70
CREW_1|FatigueStep=0.0175
CREW_2|FatigueMax=0.70
CREW_2|FatigueStep=0.0175
CREW_3|FatigueMax=0.65
CREW_3|FatigueStep=0.015 ;was .01
CREW_4|FatigueMax=0.65
CREW_4|FatigueStep=0.015
CREW_5|FatigueMax=0.60
CREW_5|FatigueStep=0.015
CREW_6|FatigueMax=0.65
CREW_6|FatigueStep=0.0125 ;was .015
CREW_7|FatigueMax=0.65
CREW_7|FatigueStep=0.0125
CREW_8|FatigueMax=0.65
CREW_8|FatigueStep=0.0125
The important variable is FatigueStep. In the original Rub models, this variable is set to 0, so the crew never recovers fatigue. I found that setting this value between .0125 and .0175 gave me the best results, but you can tweak them to your own liking (you might want to raise them slightly). By comparison, notice that the stock SH3 values range between .05 and .2
These settings will allow your crew to experience fatigue but then slowly recover if they are regularly rested in quarters. Good luck and let me know how you like these settings.