and set offsite 100, what will happen when I lose my 50 clams?
I need to add 100 or not?
I can set offsite to any number, although I don't really have?
If you have 50 CLAMs onsite and declare that you have another 100 CLAMs offsite, the site will treat your investment as if it was 150 CLAMs. You would risk up to 0.5% of your 150 CLAM investment per roll, ie. 0.75 CLAM.
When your onsite amount falls to less than 1/199th of your offsite amount, your offsite amount will be set to zero.
In your case, 1/199th of 100 is 0.50251256 CLAM. So after you lose around 49.5 CLAMs your offsite investment will be cancelled, and you will be left with around 0.5 CLAMs in your onsite investment.
You can set it to any number up to 99 times your current onsite amount.