I have a 2000 Blazer with the 4.3, I’m assuming the Safari has the same engine. My fuel gauge has the same problem, I did some research and it is a common problem for GM trucks of this vintage. Unfortunately the sending unit is part of the fuel pump assembly (~$800 to replace). I just fill up at 250 to 270 miles, usually the truck has about 3 gallons remaining. If you track a number of fill ups, you should be able to get a handle on the distance you can drive on one tank leaving a 3 or 4 gallon reserve. I don’t know about the hesitation, but it’s not good for the pump when you run out of gas.
Ed B.