Not on My Watch!
On my boats, the pool is determined by putting two fish against each other on a balance scale. At the same time. After the trip is finished.
Especially in the ocean, I would like to see anyone here put a fish on a digital scale on a boat, and give me an accurate weight. Would you call it 31.7 lbs., or 31.5 lbs. Or, wait, we have 32.1 lbs.! And, is a tenth of a pound really accurate enough to weigh-and-release? Go to a certified scale w/ hundredths of a pound. You'll puke watching the numbers roll up and down. We determine the Dock Pool at Captree w/ a certified scale, measuring to hundredths, and I'll tell you I watch it go a few hundredths w/ the breeze, and that's on land. I've weighed plenty of fish on deck, and the scale just won't serve the purpose.
If you are truly interested in releasing larger fish, don't enter the pool, or at least don't expect to win it w/ a big fish. I can't imagine I will ever deny a pool to someone who has a fish in his hands, but was beaten by a weight from a released fish, especially if it was within a few tenths. It's just not the spirit of the contest.
The pool is a contest between anglers on a head boat, to spice things up. Head boats historically kept fish for the duration of the trip- not just for a few minutes, and the pool is reflective of, and based upon, this premise. If you don't intend to keep the jumbo, think about developing a different contest, or just focus on the fishing. Releasing a big spawner should be reward enough for the trip, if that's what you really want to do.
Paul