Are the dana 35's weak: am i looking for trouble if i install the rear locker? Is it a bad choice with 373 gears?? Not alot of experience with axles...somebody have some wisdom on the subject?  

you can get away with lockers in the 35 with small tires and high gears, like your 3:73's I'd wanna stay away from larger than 33's, then the 3:73's are gonna drive you crazy, the 35 will last though if your carefull

the wisdom you speek of say's get some d44's