Here is a calculator you can use to figure out how high you have to raise the part and what focus to put into the GFUI.
Quick cheat sheet: Subtract your thickness from 1.4", that will give you the minimum standoff you need. Then, add your standoff thickness and material thickness together, then subtract 1.4", that will give you your effective focus height.
T=Thickness
S = Standoff thickness
1.4" - T = Min S
T + S - 1.4" = Effective Focus (must be between 0 and 0.5")