Use the holster finder and enter for a p226 mk25, it will ask if you have a light, you answer yes and then it asks for the type of light and off you go. I just did it, lots of options.

 

Safariland has a lot more offerings for a P320 which is a more popular LE weapon, likely the reason you're striking out.

The Tac Ops has a beavertail, the Mk25 doesn't, I have an P226 Elite also with a beavertail, that fits in a G-Code holster for a Mk-25 in their XST line, so you can see it should fit.

They have their SOC Light Holster that also has the rotating hood, for security, and a light cowling for a Mk-25 with a X300... SOC Light holster: Edge Works (tacticalholsters.com)

 

Just call Safariland, speak with a rep and let them find the correct model for your combination.

 

Yup Call them. Francis will dial you in