Odd, since I've been shimming guns for 5 years and have never done a bad one using my way. The only times they sound whiny is when people are using flat gears and there's lots of slop in the meshing.
The reason you think it'll sound chirpy is because some people overshim the bottom of the bevel and then are never able to get proper pinion engagement on it no matter how high the motor sits. If the motor doesn't engage perfectly I'll drop it down to a .3mm shim, but I've never had to go below that.
But like I said, everyone's going to tell you to do it differently