Before you go messing about with the mechanics of the printer, you need to determine what is causing your head strikes. Most of the time it's not something wrong with the print head assembly, but with the vinyl and the temperatures and alignment. Open the lid and put something in the sensors so you can run it with the lid open. I use the sticks from the cleaning swabs. Then let it run and watch the heads as they go across the vinyl to see what is happening. Most likely you will see that the vinyl is buckling and forming ridges which hit the printhead. This can be caused by many things, but the most common is incorrect heater settings. This time of year it can also come from too-dry air, necessitating that you run a humidifier in the room where the vinyl is stored and the printing takes place. Another cause can be that the bars where the vinyl is loaded need to be aligned.
If the carriage truly is drooping down and needs to be fixed, you should probably bite the bullet and call Epson to have Decision One come out to fix it. Is it still under warranty?