Going higher with a mast, is very useful with UHF and VHF. It can be useful with Wifi, but the effect is far less.
Just like in acoustics, you're dealing with reflections. And these disturb a clean signal. You need to find the top of the sine wave. But because the wavelength is just centimeters, you just move both tranceivers a bit to find max. signal strength.
Wifi is extremely good with elimination of disturbances. That's why lots of devices can operate simultaneously on the same radio channel. VHF and UHF are comparatively bad at that. Because of the longer wave length, they tend to find transmission paths that follow objects like hills and CAN follow a longer path.
We used to have offices below a saddle roof. The triangular form caused bad reflections. If I'd put a laptop on the left side of my desk, I'd get no reception at all, despite the router being only a few meters away. On the right side of the desk, reception was perfect...
You'll find all you need in the Wifi menu, cause it's basically channel numbers and signal strength you need. The rest is accomplished by walking around. I use my iphone for it, in the rare cases I still use it. The app I use most, is free and called "Wifi mapper". It's not a real serious tool, but it shows interesting stuff, like the approximate distance to the router. Have a look. The iphone is just more convenient when walking around. I used to do it with a Macbook. Sure makes you look geeky
When it comes to working in theatres, you might find interference from stuff that uses the Wifi band, but doesn't show up as a Wifi router. I know one spot where it's the alarm system. I've pointed out to management that it means their alarm system is very, very vulnerable. Of course, they don't believe me... Guess I'll have to buy a Wifi killer to demonstrate it...
What you need most, is experience. Some of my experience dates back to the times before everything was infested with "Free! Wifi!" Way back then, you'd need to look for a nearby router that was open to get connected in the wild. These days, there's 4G. So i got very lazy...