They have these In Contact rated Air Tight cans at Lowe's $20.
They take an assortment of Par20/R20 Halogen, Incandescent and LED regular base bulbs. A variety of trims are available including gimbal eyeball to aim at the screen.
They are 5 1/2 inches tall and 6 inches wide. Nice square box that we can wrap with that duct wrap to seal and quiet.
So, in the Section of soffit with just the acoustically transparent duct (Fabric on a Slinky) we surround with insulation creating the dead vent treatment, If we have to pass by a light we go up and over and stuff as much insulation as possible. around both the duct and light.
We can take an inch off the width if we use different materials, I drew it with metal 2x3 framing.
It is standard lighting which will make the electrician happy.