Excuse me, but 50 dollars to have a comforter dry cleaned?! That's hugely expensive! :O
Apart that over here the trend is that comforters are NEVER dry cleaned but wetcleaned, be them dawn filled or synthetic, but the most expensive laundry I've seen asked no more than 18 euros (25 USD)! That's a dear price! WOW!
Right now it is "high season" for washing comforters and duvets and my father struggles to keep up with all the customers, mind, ours is a smallish laundry with only 5 people working in there! But NONE is ever washed in the ILSA perc machine, they all go in the classic washing machines!
Unless your particular comforter is made of some exotic fiber, gentle wash I'd avoid it, just use standard "synthetics" if the comforter is synthetic filled, if it is dawn filled use "bulky items"/"comforters" cycle and at the end of the cycle use the highest extraction speed you can or add an additional spin. Then air-dry if the thing is synthetic or machine dry in medium/low heat if the comforter is dawn filled. Either case make sure that it is completely dry, otherwise it will stink, especially if dawn filled!
This is considering that the external is made of cotton, if it is some kind of synthetic fiber, use a medium speed but repeat twice the final spin!