Yes, they need more light. That is not likely sunburn, rather a mineral deficiency. Sunburn is more spotty/patchy, where the light builds-up heat. Remember, heat is infrared light, therefore increasing light behind glass (real glass) will increase the infrared, while filtering the ultraviolet-blue spectrum. The later is what the plants use for most of their photosynthesis.
Your choice of LEDs is right on. Blue-violet light! This is what they need supplemented. Enough red light will come through the glass. Add them ASAP and you can keep the sheer until the plants have adapted to the more intense light, or just leave it. You are supplementing the blue-violet and the red is where heat comes from.
Now, as it looks that the roots are well developed, you can acutally sit the orchids in fertilized water! They are very heavy drinkers when in active growth, as well as heavy feeders. A balanced fertilizer with additional minerals is you best choice. I keep mine constantly moist to wet in the growth season. Heat is the biggest possible enemy, in that it can overheat the medium, but most Catasetum profit strongly from warmth (80+F/30+C), the trick is not sunburning new growth. It needs some time to adjust to strong light. That said, a few burned leaves is not a major crisis, as they are efemeral.
Potting media is best changed every Spring and use sphagnum moss (not the chopped stuff for the garden!) in clear plastic pots for indoors. This allows you to observe root development (to decide when to start watering), as well as getting light to the roots, which is beneficial.
Cats are a different breed, but once you get the hang of them, they are generally easy plants and quite forgiving.
Hope this helps.
Jamie
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