Grand Prix 2 Gear ratio help

Hi I am relatively new to playing F1 games, and I particularly like the old ones like Geoff Crammond's GP2 - i am just trying to learn about how to set gears, which of course is a feature of most racing games, so i guess i could ask this elsewhere, but i not familair enough with online forums for racing games so i will enquire if that is okay

- how do it set the gears to get a higher top speed on the straights? I have read the manual but i must not be understanding it right because if ijust set teh 6th gear to high and a greater distance from the 5th gears then i get an even worse top speed than if had not touched it at all.

also what does the 64 mean in the ratios and if i set the top gear higher than 64 what is that doing? is that why i dont get higher speeds?

perhaps if someone had a screen shot of what a highest speed possible gear ratio would look like.

thanks

gears ratio should be setted in base of rear downforce and suspensions (spring and sway bar). all depends by circuit and should be think by to be fast, not to go fast. To be fast means best time on lap.
if you tell to me which circuit are you going, I ll give to you best carsetup (gears included).
thanks