I've used countless PMR fittings they really make a 'model' steam engine look top notch and add a professional flair that's otherwise pretty much impossible to achieve.
I have never used them on a toy steam engine though.
I have bought the cast tree ones and machined and tapped them, they aren't as easy as it would look and there's a LOT of work to machine these Ozsteamdemon and Mr Pete said the same.
The machined ones from PMR after taking in the machining.....are cheap!
The PMR globe valves are par excellence and the best globe valve IMO that are available to the steam hobby.