Goods issue of grams in 5-6 decimil places .00001 as example

Hi,

Im working on a high speed plating production line implementation and we stock gold in Grams I do not believe we will change this.  They currently issue in 5 decimal place example gram 00.00021 which SAP does not allow as it allows only 3 places .001.  How should we manage this, is my only option is issue a larger qty and use per unit function as goods issue .003 grams per 100 pcs?

Is there another way to manage this?

Thanks

Mark