Understanding Shrinkage in Silver Casting

Hi,
I am planning an order of quite a large object in silver that needs to be as dimensionally accurate as possible.
I am wondering how to take account of the expected shrinkage of the object from casting:
Should i scale up the model by about 2% (which is the deviation measured from previous printed objects),
or will the shapeways operators make the necessary changes to the model to ensure it's final dimensional accuracy?

I really want to get this right first time due to ithe protibitive cost.

The model is around 28x28x109mm

Is there really no one who can give an answer to this question?

2% shrinkage seems a lot for the casting process. I suggest that it is much less than that if there is any at all.

Here's some info on the silver material. https://www.shapeways.com/materials/silver-design-guidelines. Good luck with getting it printed.

Just an update in case this infomation is useful to anyone;
I went ahead and ordered the above model in silver with a 2% increase in scale and this factor turned out to be pretty much perfect.
All internal dimensions remained within telorances and the threads were all very good.

Here are a few pictures of the finished light:













Thanks Shapeways.