Normally, there's a lot to be said in the OP's position for the Edinburgh suburbs right on the Bypass e.g. Colinton because they have decent space, are a very fast bus ride to the centre of town for shopping/boozing/whatever, and are right on the Bypass for when you need to drive to whatever worksite you're going to.
But OP has said that he doesn't want to live in a city (even though Edinburgh isn't exactly Tokyo to start 😉 ), so for the sake of convenience and low cost, I'd agree with the consensus and say a village/small town outside Stirling. Doune is supposed to be OK, too, isn't it?
I'd be hesitant to live towards Perth if only because everyone (e.g. on the speeding thread) says that the A7 is a nightmare, and if you're going to be going from Perth to anywhere south or in the central belt, you'll end up doing an hour on it every time.
Of course the really big question would be if there is any way the OP can get a better idea of how many sites s/he'll be working at and where the calls tend to centre on.