How powerful of a pump is required for a regular r134a system such as that in the 94 e320 (w124)?

Would a 1/2 hp model be adequate?

I have the opportunity to buy a Duo Seal Mo. 1402 at a reasonable price and want to make sure that I could use it for A/C system evacuation.\

I found an eBay auction for the same model indicating it could draw 29.9 inHg is this adequate?

Thanks!

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE