Hi I'm a clarinetist... Personally I wouldn't start playing at all without multi-phonic fingerings... so I think you had better take all of the initiative in that department.
flint is right, I wrote a piece for flute, and luckily Robert Dick wrote "The Other Flute" which helped me more than I can fathom. I don't know of a clarinet equivalent tho :\
As for the sound of the multi-phonics... lol it will surely be intense. Flute comes out really wispy, but the clarinet will be harsher because the reed is freaking out.
However, if you give me what you suspect as the multi phonic fingerings, I would be delighted to help you out
