Zig racker install

[xjwalt666]

I’ve searched around a bit here and on google and haven’t found a real answer. Also contacted Brazo’s and haven’t received a solid answer. 
 

I just picked up a new to me Steelmaster. I want to put a zig racker on however it is not flat topped. I know that they are designed for a flat topped slide but I don’t want to do the top cut until spring when I can get the slide coated. The instructions say for a .036” flat top. So if I were to add .036” to the .187” drop for the dovetail would that get me what I need until I cut the slide in the spring?