With orbit lines keep the green line just visible at the top of the screen then max throttle. Same thing on the sides of the screen which is a slightly farther distance from the sun so a little longer refuelling. No hurry then same top of the screen alignment at max throttle and once you start fuel scooping come to a compete stop. It takes longer but never overheats. Time to love your pet, get a beverage or read some posts on the Forum.
The warning is at 80 percent but no damage as I never go past 85. When the ship is almost full one can go to the next destination before overheating. My general rule for most ships is a fuel scoop one class larger than the fuel tank. Both the same class may hit the 80 percent warning sooner. One class lower as in a Diamondback Explorer and longer slower refuelling. Deep space explorers love it but hate the fuel scooping.
Here is a
build that cruises at 16 percent heat, can max throttle green line orbit a sun all day long never going over 65 percent, and a 65 light year jump range. It is for quickly going wherever I want to go and after multiple jumps without fuel suns down to 10 percent can completely refuel fast at a KGBFOAM type sun. It is power sensitive so when deploying hard points turn off (priority set to 3) non-essentials as in the fuel scoop, docking computer, vehicle hangar etc and it flies just fine. Then it is not really designed for combat. I named it 'Cool Running'.
Regards