I've recently converted to the GWS DD tail rotor on my blade and love the way the tail works BUT...... The mounting bracket from GWS is the most fragile part of th heli now. Even minor crashes will break the fin and motor mount. Is there any better, stronger way to mount the DD motor on my blade?

yeah, mount it in the stock tail motor holder. You'll need to shave off a bit though with a dremel or something. Check out this pic from kyle stacy's chopper

this puts the prop on the opposite side from the GWS mounts. Do I then just reverse direction of the prop?

yeah, that's the way you want it, the way above with put the brushes in the appropriate lead/lag position so you don't get prmature motor failure.