Rationing futures by ATR(20) on 17.02.2011

Silver, to date, the most volatile of the futures at the price of one ATR(20). I.e, for example, if you open a position at 1 Silver contract, then Natural gas, if you stick to the same risks, need to open 3.15 contract, but since 3.15 can not be, must be rounded to 3. Respectively, if Silver 10, then Natural gas 31 the contract.