Chilled Cast iron - Camshat/Tappet

Looking for guidance to achieve the following in chill cast iron (Camshaft/Tappet) in the foundry. 1. How to control the chill depth? 2. How to avoid/Minimize the mottled zone? [login to view URL] to get the columnar zone in chill zone? We will give full details once the project awarded. Based on trail only project will be approved. Trails can be done at our end based on your input (Only 3 times trail allowed per person). Gray cast iron TAPPET considered for Trail. Once all requirement achieved in tappet then we can proceed for CAMSHAFT trails. Your guidance required upto mass production. Your guideance should be in details (Very Specific - Ex Si% - 3.2%) 50% Payment will be released based on the camshaft trail results only. Another 25% payment release based on mass production of tappet. Another 25% payment released based on mass production of camshaft