After getting the screw heads off, I was able to remove the burners, then gently push the holders down until the tops of the machine screws cleared the drip pan. Looking online, it looked like I'd have to do major surgery to get the top off (i.e., the directions I found required me to remove both panels from the back of the range, along with the securing screws for the control knob panel and four securing screws that held down the front of the drop pan. Turns out the job only requires removing the control knobs, the two screws that hold the control knob panel in place, and four other screws that are exposed after removing the control knob panel (two at the outer edges, and two about a foot in from each edge). Then you just need to tug the drop pan forward. Two things to watch out for: if you're in my situation, you need to make sure the remaining machine screws that protrude through the drip pan are pressed down far enough to clear, and you'll need to look under the front edge as you pull, to make sure you clear the two tabs that held securing screws past the frame of the range. Once the pan's moved forward about half an inch, you can lift the front up and then remove the drip pan. The attachment holes in the holders did not come with securing screws, and did not have threads cut into them; I used a #8/32 tap, and bought 1" machine screws at my local Home Depot. After replacing the holders, it's important to pull them up, gently bending the gas supply line so that, once the drip pan is back in place, they press against the bottom of the pan. Replacing the drip pan simply requires you to set it in place (forward of its ultimate location); look under the front edge and slide the pan back so that the two tabs clear the range frame. Secure the front end and the control knob panel with the (Torx #20) screws. Then grab the center of each holder with a pair of pliers, and gently twist the holder so that the screw threads line up with the holes in the drop pan. Then it's just a matter of setting the burner on the drop pan, and getting the machine screws to thread into the holders.