If it is over 8", its just like any other trout, under, you have the special extended limit. So, you could theoretically keep 12 brookies, as long as only 4 are over 8". And honestly it is probably a really good idea to at least try to hammer out that under 8" limit! Nearly every single brook trout stream/lake I've ever fished is horribly over populated (hence the reason for that limit increase) and they start to stunt very quickly. And wouldn't you know it...brookies are among the best eating of the trout family!