I killed my share of stuff with light fast arrows over the years, including 10ish roosies, same amount of blacktail, and a couple bear with arrows in the 380-400gr range. the past few years, 5 or 6, I have bumped my arrow weight up, not because I was having problems, but because I wanted to try something different and that made sense.
the last several years I have shot between 480-642gr out of my compounds, which has killed stuff just as dead, with coincidentally or not less reaction to the shot (that theory isn't one I would change my arrow setup for, but there has been a pattern)
I will say I will never again shoot less than 500gr, not because it's needed to kill stuff, but it quiets the bow a lot, and makes fixed head flight way more forgiving... it makes a lot of sense, especially when you shoot the same target with the same pin with a light arrow and heavy arrow and there is way less difference in point of impact than most would guess.
example, I shot a 440gr arrow and a 585gr arrow out of my 70lb triax at the time shooting 70lbs and 28" mods (just over 28.5" draw length) and there was basically no difference to 30yds, and 4" @ 50yds... not a big deal in practical terms.
if you like light and fast, by all means, I shot a lot of critters with that type of setup, and it always worked, but it won't hurt to try a heavier arrow that is spined correctly for your rig so you have a good idea what you prefer.
hunting on the coast, there is gonna be shooting through some stuff, even if you try not too, there's often something between you and the critter, a heavier arrow is way less sensitive to deflections (within reason of course) and just fits what I do much better.... maybe a lighter arrow fits your needs better, you would know more than me.
i'm a proponent of building an arrow setup that perfectly tailors to your needs, whichever that may mean. I don't see any benefit of going below 425gr for anything, but if you do, I won't say you're wrong... especially if you are killing critters with it.
I like higher foc, but not full Ashby on it, if I build an arrow that flies good for me and it's 14% foc i'm not going to feel insecure about it, haha.... I know well enough that I like avoiding the extremes, whether it's fast and light or heavy EFOC.... somewhere in the middle is where I like to be after doing some really heavy high foc builds... unnecessary to me, bow is quiet and forgiving without getting crazy.
I do tend to build heavier higher foc arrows for my recurve, and it's more about getting the arrow speed that my mind likes... there is a range of trajectories that I shoot better... too light and i'm constantly shooting high, too heavy and i'm shooting low and the arrow is falling out the bottom too fast... different deal altogether.
modern compounds have energy to spare, so no reason to split hairs on arrow builds, lots of them work. I say stay in the middle of the extremes, and favor whatever end of the spectrum that fits your needs the best. don't listen to those who say YOU need to shoot 300fps hunting arrows, or the ones that say YOU need 650gr hunting arrows.... you don't, and the extremes are very specific, not good for an all around hunting arrow imo.
one of the most versatile arrows is a 5mm axis in your spine range with a 50gr brass HIT and a 125gr head.... still may not be best suited for what you do, but painting with a broad brush, it's a good do all arrow.
