I've mounted a bunch on different vehicles including Tahoes. The best way to go about it is the get vehicle specific mounting hardware from the respective manufacturer. They utilize the mounts for the sun visor, essentially sandwiching between the headliner and the visor mounts. This will also keep the lights mounted as high has possible while retaining full use of your visors. They are usually fairly strong brackets and wedge themselves against the glass to keep them from flopping around. Rubber trim lock sits between the light and the glass. Some adjustment may be needed.
You could definitely DIY it with a couple custom aluminum brackets and such, but it will be a huge PITA. Another thing to be careful of is glare when the lights are on. If there is space between the housings and the windshield you will blind yourself from the reflection every time you turn the lights on.
The wiring will run under the headliner and down the pillar. Remove the plastic cover and zip tie the wiring where you can. Be very careful of airbags in these areas.