O.K this can be a combination of things smoke level, performance, sound and heat your engine should have very little smoke at idle but plenty at high speed without bogging down, heat is personal preferance but i try to run my engines at about 95-100 degrees celsius for long life at maybe a slight but unnoticeable performance lag. If your car takes off like a rocket it's too lean at the bottom end or idling too high and riding the clutch if it idles inconsistently then settings are wrong if it suddenly rises then lowers and then rises etc. it's too lean if it chokes and splutters it's too rich. If it hits top end well then check temps, i use the spit test i try to get spit to not boil at all or at leat very slowly then it's about 95 c. for longest life use 0 nitro!!!! but for a .21 you can use up to 25 safely. If by the new way you mean the stephen bess method i would not reccomend it unless you have a picco engine, just take it slow run it rich and slowly increase performance over at the very least 6 tanks, but should be more.

Heat should be fairly stable across revs so if it overheats at low then i's too lean on the bottom if it overheats at high revs it's too lean on the top (Not completely sure about that last one, but fairly)