Don't be jerk like me try it with just one person....
Too late....
Here's the 12-step program by which I do it all the time by myself on a Mk II:
1. One time only, tie down all but the last few inches of each wiring harness in an appropriate place so they're not flying around getting hooked on things.
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2. Open boot lid, disconnect harnesses.
3. Unlatch clip on each side.
4. Lift clip up at the rear enough to clear fuel fillers. It will rest with its corners on the tires.
5. Place moving blanket, cardboard, or similar under the front to give clip something soft to land and slide on.
6. Standing front and center, open and hold boot lid about midway on each side and use it to lift the whole clip up at the rear. Good core strength helps. Walk backwards with it and set it on the blanket-covered ground. I don't know how you would do this with a Mk I, but you can figure that out. You just need a way to grab the clip a little to the rear of its center of gravity. A couple of cleverly attached nylon belt loops would do, or maybe a pole that is a little longer than the width of the lid opening.
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7. Assembly is the reverse of disassembly: while holding the clip by the lid you need to guide the subframe spools into their receivers while lifting the lid enough at the rears that its rear corners will "slide" over the tires to the "almost on" position you achieved in step 4.
8. Once that's done, stand at the front, hold the clip with both hands under the radiator opening, and give it a good shove upward and rearward. As the clip passes over the fillers it will probably open both of them (you needed to put in more gas, right?).
9. Go back and lift up each rear corner enough to close the fillers and set the clip back down.
10. Latch clip.
11. Connect wiring.
12. Close lid.
PS: if you really wanted to make this slick (so to speak) you would add small nylon bumpers or Teflon sheet or rollers, etc., in a few key places after which you would not need the blanket and the rear corners would slide smoothly over the tire surfaces.
PPS: adjusting the spacers behind the subframe spools, and their eccentric positions, helps a lot in allowing the clip to slide on smoothly.