That was dinner last night for friends. I chose to do the rack on the grill, indirect, low, with a temp probe. This rendered the air around the racks around 250, just where I like it in order to get that medium rare right to the edge and not just the center.
Once the rack got to 120ish, internal, I went full high on both burners, brushed both sides lightly with the glaze I had reduced from beef stock and bit of lard & duck fat (and very slight bit — 1/3 tsp — of chopped jalapeno that I later strained out). Then, we turned 'em a few times as the temp rose to about 125-128 internal, then let 'em rest for about five minutes before slicing, glazing, and garnishing with freshly grated parmesan.
And a final close-up (click on 'er to enlarge).