1/4" line down to 3/16" from MC to Prop Vlv

[67CamNKC]

I have my late model booster and MC from mounted on my 67 camaro. I also bought SSBC's prop valve (shown below). I need to build a line or use an adapter for the front 1/4" MC line (rear brakes) to reduce to the 3/16 line for prop vlv. Is there an adapter that will thread into the MC (M12x1) that I can thread a M10 or 3/16 bubble or inverted flare into (something similar to the brass fitting in the Prop vlv pic)?