What about scoring the fish the way asian chefs do.Carefully slice into the fish a couple of times and then spread your paste or seasoning over the fish and into the slots.Be careful though as this will also speed up the cooking process by allowing heat into the fish faster.You have to remember that the skin on the fish is its own source of protection or body armor against other sea life and can't be easily penetrated by herbs and seasonings. Also you are seasoning the cavity of the fish,right? Sometimes I will even marinate fish filets in something like red wine(with the alco cooked off) over night. It is flavorful and takes on a unique purplish red color. This may make some chefs cringe, but at home I like to think outside the box and not do everything so strickly.You are feeding yourself afterall and wont be hunted down by the culinary 5.0