Turbo need cooled down to oil temp in a perfect world. If the truck has been run hard, or in stop/go traffic or in town, about 5mins.
A pyro is a good idea, the go in the exhaust as close to the output of the turbo as possible. Most truck parts companies can order a pyro setup for you. Truckpro, fleetpride, napa, etc.
They are really easy to hook up, you drill a hole in the exhaust pipe, weld in the nut that comes in the kit, screw in pyro sender, run and connect the two wires from sender to gauge, and hook power up.
That's an easy piece of insurance for your truck. Make sure you buy a good brand setup. Yes, the good ones cost around 200.00-300.00.
A boost gauge, is a good way to see the power the turbo is putting out, but not as important as a pyro setup.
If you need more info or help let me know.