I recently got a 129-- a SL600! Researched what to do about top removal and storage. Bottom Line go to http://www.eztop.com (The Hard Top Hoist Company) (713) 694-4505. Buy the electric hoist ($595) DO IT RIGHT

Reasoning: The only SAFE way to lift the top is: either with 2 people with strong backs (not the weight, but awkard long reach required), OR an electric lift that allows you to guide the top and control the lift at the same time.

A dropped top (onto the car) will cause paint and worse damage minimum $250 to repair-. Top is easily damaged by incorrect storage and will LEAK like a seive.

I am an engineer, and KNEW I could put together a rig cheaper--but it would take at least 2 full days of 'Wilbur Wright Design' and purchasing over 2 weekends, plus another day of assembly, and would cost a minimiu of three hundred bucks in quality parts--and it still would not come close to the thought, design effort, and safety features (both human and protection of the top and car) incorporated in the eztop hoist.

NEVER lift something valuable over something even more valuable using cheap junk hardware. BUY U.S. industrial quality to have reasonable confidence the pulleys won't shatter at first loading.
I am a tightwad, but try to evaluate risk/benefit of going cheap. This ain't the place, and the price is small.