If price is an issue, why don't you just do half the zones at first?  you can always add more zones as more money frees up and you will have a way more bullet proof system.  as far as your "zones" are they 6 seperate rooms or are they multiple switches in a few rooms? 
i honestly think using urc will be way more reliable and you won't tie up any outputs on your mrf 350, believe me they go fast.  be smart with your money and grow into your system.  i guarantee you will save yourself more in the end.  time is money no matter how you look at it.