The way to load Trail Boss, in anything-according to Hogdon, is fill up the case & seat the bullet, but don't compress it because this destroys accuracy. I have found that in most chamberings this still makes a supersonic load, not the real sharp crack, somewhat like a muzzleloader.
In order to make a subsonic load you have to cut way back on the powder, & then we have to be concerned about the bullet clearing the barrel.
I know what you mean about the neighbors, but I'm going to keep shooting. I feel the less we shoot, the less they"ll expect us to shoot. I'm trying to come up with a "tube" or a "booth" that will knock down the sound, but we still have to deal with the sonic crack. - Good Shooting - Jim