altitude and humidity factors

how does said affect tuning, i am at 3500 ft and its been 90 % for so long I/ve forgotten, i read once that around 3000 ft one should consider jet/adjustment change ... experts ???? and humidity as well ???

Higher altitude as well as warmer air will cause your setting to be Richer than lower altitudes and colder air.
Don't go changing jet sizes without making sure of all other systems are correct. Ignition perfect, spark, timing, advancer function/ Compression/ No vacuum leaks/ carb's cleaned, floats set, and carb's synced, fresh air & fuel filters/ and have been doing plug readings, and mileage figures, Then if you determine adjustment is necessary, adjust jetting.
If you believe you are at that point now, Post up all model info, carbs, all jet sizes, and if you can plug pic's. There are guys who can get you a setting that's real close, if you need that.

After you find out your jet sizes,etc.,etc. You might want to check out the thread on "Interesting Reading" about bad air. Just a suggestion, take it for what it's worth.