Relatively easy option
Saw this late, but after a bit of messing around with electric top issues, I accessed the switch and measured it to verify wiring. The fuse is supposed to be either near the switch or behind the drivers seat belt wall panel which is a pain in the *** to access. All switches should be wired similarly, but you should measure your switch. They should all be wired with the middle contacts ground (W in my case) on one side, 12v (R in my case) on the other. Then the Up wires are split using lamp wire near the switch connection as are the down voltage runs. I think its safe to assume each leg of the lamp wire goes to each motor. It would be much easier to jump the switch wires, and very much easier to test for voltage at the switch. I had an odd Blue pigtail wire female plug I could see from the back side (Up voltage). So if you couldn't lower (or raise) your top, best would be to access the switch connections, preferably test with a voltmeter, pick a corner pin (top?) and apply 12v to one side, and Gnd to the adjacent side. The motors would go up or down. I am also guessing the motors are body grounded, but my ground white wire could go back to the motors. Anyway this picture/schematic/cartoon combination should be helpful. The lamp cord split in the wires off the top is shown in the cartoon. The reason for the split runs is the Linak LA31 actuators each draw ~7A under load. The actuators reverse with reverse polarity. Someone mentioned using an electric drill battery (assuming 12-14v), but a jumper wire with maybe a 20+A fuse in line could do nicely.
Mechanically lowering the top looks to be very difficult as it is pretty loaded and constrained.....Congrats to the OP for their success.
Pac NW and warmer places
1995 E250 EB 5.8 2WD on to a new owner
2006 E350 EB Elect Top 2WD