really need help with this one!, throttle body gap Options

[replica250]

hi all im still having low and uneven idle problems with my gt st202, i did a full survive, magnicor leads and irudum plugs, arm and cap, all filters and oil and reset the timeing 10 degrees btdc with the two point in the multi plug brigded as the last owner had it over over advansed, new samco rad hoses and rad fluid, got a massive air lock wich was a pig to get rid of but am still loesing water, the same amount no more no less and the expancion tank level never changes so im asuming the cap is leacking steam but cant be sure so today orded a new rad cap, and changed the engine coolent tep sensor.
but it still dont want to play ball,
my throttle stop screw has been moved at some point as theres no paint on it and i was wondering if any one knew how to rest the butterfly gap as it not going to run properly untill its back to standard, the guy that owned this car before was a trainee grease munky, what a dickhead!
so does any one please plaese know how to reset the throttle body, ihave a feeler guage just need to now what to do, rusty im looking at you!
buy the way the idel sits under the last line before the 1k line and if it ever sits inbetween its so smooth its like the car isnt running at all, who designs a car with no idle ajustment screw?...