FYI - a Proof Sendero light closes matches Rem Varmint/Sendero contour. The Proof Sendero is actually bigger than a standard Sendero or Rem Varmint. I believe this is on the website; maybe in FAQ section. I’ve read this many times; just not recently.
As mentioned, all the dimensions are listed. Also, you will be good to go if you drop a Sendero light in a Rem Varmint/Sendero cut barrel channel.