if your DS is 'totally spoiled' glitch then so is DD

i could have written both your posts in this thread - and highlighted for me, at least, one of the hardest things about parenting a child on the Austistic Spectrum... we have to try to stay constant to prevent any triggers - sod our own feelings and misgivings 
DD can wail - open mouthed on a constant noise level - for a half an hour some days, especially if we're in the car
sometimes leaving her in her safe place but putting some music on elsewhere in the house can bring her out of it, but most often we run her a warm bath with loads of bubbles and leave her to splash about until she's able to converse again.
i've recently learnt that once she's in wailing mode there is not a chance of verbal communication with her until she's ready - if i need an answer from her i use hand signals 'do you need me to do anything, point to this hand for yes, the other hand for no'. she sometimes won't even point, she'll look and use her eyes instead. if she indicates "no" then i tell her i'm going to leave her where she is, that i'm not ignoring her, just letting her do what she wants for a while.
i'm also in the process of making some picture cards for her, i don't want to turn into a household that leaves notes about for each other, but sometimes talking is too much.