If you do not want to use any margin at all, I believe your options should be set like this :
Margin requirements :
Long Initial : 100% ( Means 100% of your money nothing else )
Long Maintenance : 0%
Short Initial : 200%
Short Maintenance : 101%
I have to double check on that though but I'm pretty sure this is right.
EDIT - it is the right answer 8)
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