(I can only provide feedback on the conditions where this species grows in the wild, as it is fairly common near the house of my parent in Vzla. and my favorite Cattleya at all)
this species can be divided in two groups (it's me now dividing it, so possibly no taxonomical value! It is based on my observations in Venezuela, and probably not applicable to brazilian plants):
Plants growing in the amazonian forest: normally the flowers are softer and thinner, but also better general shape and lighter colours. Most albas and semi-albas seem to come from this group.
Plants NOT growing in the amazonian forest (
easy grouping, isn't it?): Thicker flowers with darker colours. Petals thinner, and therefore more star shaped than the amazonian cousins.
Both groups: they normally grow next to rivers (Gallery forests) and therefore are exposed to high air humidity most of the year. Sometimes they even grow just next to the water, but without been in contact with it. However, the normal case is growing a bit high on the trees! The rainy season for both plants is differently defined:
Amazonian group: it rains every single day of the year. dry season (5 months/year), normally one hour in the morning and sometimes also in the evening. Rainy season (7 months/year), it rains almost all day long every single day. Temperatures for this group are normally lower than for the other (YES, believe it or not, the amazonian forest can be sometimes a bit cool!), however they normally do not go below 20°C (let's put an average of 28 - 30°C, but near the Tepuis - Meseta like mountains in north amazonian - it can be an average of 25°C and can go down to 18°C).
Other group: dry season, no rain at all during 5-6 months. Very, very dry and hot (daily temps of up to 40°C!). Due to deciduous forest, this plants are normally exposed to more light than others (especially during this season). Rainy season, it rains very strong every single day for 1 - 2 hours. Just after the rain, the sun shine and the plants are dry rather quick!
last note: I have some plants growing on trees in the house of my parents. At the beginning I gave them a quite conservative treatment with light, mounting them on trees with a little more shade (however, enough light Cattleya mosiae and lueddemaniana, and Brassavola cucullata), because they humidity was not to high. They grew perfectly for several years, but did not bloom until I moved them to trees where they were exposed to more light and drier air! They bloom every single year for easter time since then...
I hope this helps to understand the needs of this species.