- I noticed you are posting from Monterrey, Mexico. This happens to be in the middle of the natural occurrence range for Taxodium mucronatum, the ahuehuete, or Montezuma bald cypress. Are you working with T. mucronatum or are you working with the Taxodium distichum, the bald cypress, who's native range is pretty much limited to inside the USA. Now seeds, seedlings and forestry projects have spread T. distichum, the USA bald cypress all over the world. So you easily could have access to either species. Do you know which you have?
Which species you have is only moderately important. The USA bald cypress, T. distichum thrives in flooded habitats, and many grow them in pots partially or even completely submerged in water. The Montezuma cypress, or ahuehuete, T. mucronatum comes from river bank and wetland edges where it is only flooded for parts of the year. I have no hands on experience with T. mucronatum, but I suspect it would suffer if grown submerged for the entire summer the way many in the USA grow T distichum. Both species grow quite well if soil is kept moist, with no need to submerge them. So if you do not know which species you have, simply grow them more like a conventional deciduous tree, keeping soil moist through the summer but not submerging the pot in a tray of water.
I have grown T. distichum, for a decade or two. The leaves do reduce, though the leaf reduction is not as dramatic as with elms (Ulmus). Distichum has the habit of dropping first year branches over winter, keeping only a few new branches each season. They do eventually ramify, but the ramification is coarse as mentioned by others. My guess is you can depend on maybe a 50% reduction in leaf size with a few years of ramification. Each leaf is a frond, you can think of the frond as a representative of a small branch with single leaf blades. So the feathery look of the leaves does keep the image light, the fronds do not give the impression of overly large leaves.
I do not know ultimate leaf reduction. It may be possible to get smaller leaves than the 50% or so reduction I've seen. Mid-summer defoliation can certainly help, or defoliation about 4 to 6 weeks before an exhibit to refine leaf size for an event that will be judged. And as also mentioned by previous posters, you can take a scissors and shorten the length of the fronds if needed.
or others more experienced with bald cypress can comment about ultimate limits of potential leaf reduction.