I have largely the same experience as you,
@LittleDingus.
I have a bald cypress, a coast redwood, and two dawn redwoods. I keep the bald cypress in standing water for months at a time, starting as soon as it starts getting hot in late spring, until it really starts cooling down in the fall.
While the redwoods seem to want more water than just a daily watering (or two), they also seem to resent the same treatment as the bald cypress, i.e. sitting in standing water for extended periods of time. So, while it's definitely not scientific, I've found the redwoods seem to like being left sitting in a tray of standing water for a couple days at a time, then I take them out and water them "normally" for a few days, and then back into some standing water, etc...z