I just went thru this crap when I rebuilt my 4.0 in my 95 Xploder. And no, that tool doen't work. You do need a test harness and an ohm meter. You need to set it up on TDC, then turn the crank clockwise 28 degrees. Being there's no 28 degree mark you just simply cut a piece of paper EXACTLY 34 mm. long and that will give you the specified 28 degrees. You have to rotate the cam sensor untill you find that the ohms drop to zero at the 28 degree mark, then lock it in. Make damn sure you're right on that 28 degree mark when it drops. It's a pain in the ass to do with the intake on for sure!
Oh and of course make sure your crank sensor in on cuz if not you don't have your pointer to show your timing mark.