this past spring i tried  the "special red spice" and it was great!!
i carry some aluminum foil "baking" bags in the biggest size they make.
before i leave home, i cut them length wise in half.
when i get a nice laker, i cut the head off and clean the cavity.i slice some onions and mix up some "SRS" and pour over onions in cavity.
i lay fish in bag and if it's to long ;D, i use the other half of bag to overlap the first one and fold and seal the one edge and both ends.
then after i have a good base of hot coals i lay thye trout on a small backpacker grate over fire( no firepit grill in the Q).
after about 30 min, i take a sharp knife and pierce the foil and the thickest spot.
if it slides in easy half way or more, i flip over using my trusty leather gloves and grill another 30 min or until knife passes thru easily.
lakers are naturally fatty, so the first hole i pierced allows the extra fat to drip into fire, so watch for flare-ups?
when i open the foil i just grab the backbone and lift gently and you take out all the bones and what's left is just fish fit for a MAYAN king and there's almost no wasted meat.
i like this method because even a small trout go's a long way!
as it cooks the SRS runs out and coats the skin and gives it a reddish color, sorta like dry rub ribs get when grilled!!
not "hot" but very flavorful and spicy ;D ;D.
i burn the foil in fire to clean fish remains off it and next morning, i add the foil to my garbage bag.