If the temp get high when the car is just idling, you need to richen the LSN. If, while idling it stays somewhere between 200 and 220, you're okay.
When running the car hard, and it gets too hot, you need to richen the HSN.
Each needle serves a different purpose. Some people just adjust the HSN when it runs too hot, and that affects top end only, but will not correct the problem if the LSN is too lean.
I don't know the best temp for that particular engine, but most engines are still safe under 280.
Your HSN needs to be adjusted for performance according to outside temp and humidity.
The LSN, as long as it has good pick up from a stand still, is fine in any temp or humidity.
To richen, turn left, or counterclockwise, like a water faucet handle. To lean it, turn it to the right. Don't turn more than 1/16th at a time, then test it. If it got worse, turn it 1/8th the other way.
Tune by ear and performance. When it's running good, check the temp.