I think you have the right idea, Bald Cypress is the easier to use stand in for a ''redwood''.
Quite honestly, the foliage of a Sequoiadendron gigantea - Giant Sequoia - foliage looks rather like a juniper. Why not style a Shimpaku juniper to mimic a Sequoia. For shimpaku you will have to train it from a young age to have a straight trunk. Or any of the more upright juniper species. Yes there is the cache of pointing to a small tree and be able to announce "that is a giant sequoia", but for a more convincing image, a juniper is a good stand in for a sequoia, Junipers are the ''silly putty'' of the bonsai world.
I have a dawn redwood forest, and it survives my winters, zone 5, roughly -25 C or -17 F as the coldest one or two nights a year, average mid winter night temp is about +10 F or - 12 C. The pots are set on the ground, sheltered a bit, but not entirely from wind, exposed to snow. They come back just fine, no loss of fine branches. So far branching is coarse, each compound leaf ends up representing a fine branch. Looks pretty good, but not sure how well I can keep it shaped, it wants to grow aggressively. Dawn redwood is a very rapid growing tree when given enough water and sun.