Would you repot this cattleya now?
 

I just received this cattleya from an eBay merchant. It has almost no back in the pot. I water it twice a week and mist it one a day in between. Would you repot it now given that there is virtually no bark around the roots?

Repot when new roots are emerging.

Bark and other potting media are for our benefit, to retain water, hold the plant upright. Give moisture and nutrients, the plant can stay bareroot.

My humidity is low (less than 35%.) Would you water it more frequently than twice a week (by "water" I mean pour distilled water over it for a few seconds until it's saturated--or should I immerse it in water for ten minutes or so?)

I don't know. That is part of the learning process. Besides RH, other variables include light and temps. The good thing about having little to no media is you likely won't overwater. If the leaves are thinning and the pbulbs start to wrinkle, you are under-watering. If you are more comfortable with media, add some. Just don't expect the roots to attach, the plant is currently adapted to little/no media. New roots will adapt to a pot full of media. A compromise might be to put it in a UNGLAZED clay pot.

I'm just giving conventional wisdom. Others might be by with specific advice. Whatever you choose to do, to be successful, you will have to adapt until the plant has adapted (usually new growth).

I'm not much of a Catt grower. When I grew Catts, I grew them S/H (I've since given them a way). The alliance plants I still have are all mounted.

Can you put it in an open baggie or a terrarium? That will give it more humidity until you repot. That's what the OB advised me to do.

That's a thought.

With a plant that is all wound up with a basket, I just drop the whole thing (basket and all) in a larger pot, or basket, fill in with large bark and figure the plant will just grow into the new medium. Even when it's making new roots,, getting it out of that basket without damaging the existing roots (which are very good) is going to be very difficult - I see no good reason to even try.

It's a seedling. It can't tolerate drying out as much as an adult plant can. In that net pot you need to get the roots wet every day. In your humidity I would put it into a glass of water for an hour or so every day. Misting doesn't do anything useful. It can increase risk of fungus attack, so stop doing that.

You need to decide how you want to grow it after it gets bigger: In a basket like it is? In a pot with medium? Baskets need watering almost every day until the plant is mature. Pots need watering less often.

If you are going to grow it in a basket, you can drop it into a new basket whenever you feel like it. There is no point to doing this until it starts growing, though.

If you are going to grow it in a pot, do not remove it from the basket when you are ready to pot it up. Just put the basket in the new pot and fill around it with your new medium. There is no reason to disturb the roots repotting.

What are your ambient temperatures? Seedlings usually prefer being a little warmer in winter than some people keep their houses.

Temperature range is 68-78F.

That range should be fine. Water it every day in that basket. It will start growing before you know it.