Do not continue Petromalt as a preventative as it reduces vitamin absorption. If you can't find an ingredient or are out of one its ok, this is just a guideline. E to where it is just glossy, but not oily. The oil is mostly for EFA's and coat conditioners and the E is said to help with fertility. Please use caution if adding corn to the mix, it is a hot feed and will encourage hair regrowth and make your bunny fat and flabby.
Corn is good in very cold weather, and rabbit do love it.
I find that a slicker brush works great for under and around the legs, and a pin brush for top coat. Be very gentle and your rabbit will enjoy grooming time. I am asked frequently about how often to groom and it seems as the rabbits coat will tell you. Baby coats to six months old tend to take more time, and tangle more. At about six months, and less frequently as they age angoras will shed their coats, this can be over time or very quickly.