Hi Kybasche.
My Tols are all on placques, except for 2 which are in little thumb pots with but a single chunk of charcoal that they cling on to.
I have them all mounted on hooks on an ex-grill rack that hangs in one of my south greenhouse windows. I hose them down daily , the thumb pots get taken down and submerged for a couple seconds in the same rain water I collect for all my orchids. Charcoal doesn't really absorb much water, so I don't think charcoal in a little pot will rot your roots.
When I want to get sphagnum out of a plant, I get some tepid rain water in a fairly shallow pan, enough to sort of "float" the plant, and then tease the spahgnum away from the roots as the water helps loosen it up a bit.
I don't worry too much if I lose a few roots,(try to be careful with those green-tipped ones and the ones closest to the plant!), as I hope my healthy plant will grow new ones. If I were dividing a plant, I think it would be about the same thing, as far as some root loss goes, anyway.
Once most,(or all, if you are really good at it), of the sphagnum is removed, I mount the plant on a placque. A couple stray strands of sphagnum won't hurt a placque mounted plant, way less of a problem than a plant buried in a pot with a ball of soggy sphagnum down in there....
Those roots adhere themself at a microscopic level to any porous or pitted or rough surface. Since terra cotta pots are quite porous,(think of how they absorb water), orchids adhere themselves rather readily to the surface, can be torn rather traumatically by trying to separate the fat lovely root from the clay. That is why Leisurely suggested breaking the clay pots and then stting them down inside a net pot.
Another quick clue about Tolumnias;
Some like to regrow bloom spikes off the previous spike, so don't cut the spike back until it's dead for certain.
You can fit a LOT of Tolumnias onto an ex-grill rack.....