All very well said, Leo.....and a good point about the virus risk. I have not made some crosses with my Cattleyas because I had this same concern.
If you use the suspected virused plant as the capsule parent, and then allow the seed capsules to mature to dry seed, sowing the seed only after it is dry - the seed will be free of virus. Green pod seed culture is off limits if you suspect virus. Selfing a virused plant and letting it go to mature seed pod & dry seed is a good way to clean virus out of a genetic strain or line. Any sap transfered in handling green pods can carry the virus and infect the mother flasks.
Actually it was Arnie Klehm who was my original source for this information on viruses. I had been offered a known virused plant, and was asking how to handle it so that I wouldn't infect my other plants. After an hour or so of back and forth discussion, I chose to not accept the virused plant from the 3rd party, even though it was a very rare in the US plant (Lycaste mathiasae). Sadly the 3rd party didn't want to risk having a virused plant in their collection, and destroyed the plant before a safe home could be found for it. I don't know if this species is still in cultivation. A sad little tale from some 20 years ago.
Anti Virus Keys:
1.) Wash hands between touching virused and non-virused plants.
2.) sterilize cutting tools between plants, I use single edge razor blade and just throw them out after use. (in a metal tin, then into the recycling bin).
3.) absolutely keep all sucking insect infestations to zero. It is documented that aphids can transfer bean mossaic virus from plant to plant, I suspect (but have no proof) that they can transfer other viruses as well. In the same light, I also suspect that other sucking insects might be able to move virus from one orchid to another.
4.) If a plant is suspected of being virused, do not let its leaves touch other plants. Keep a segregated, spacially separate area for virused plants.
5.) sterilize pots before re-use, also never transfer used media from one plant to another.
There may be more steps, but this is what comes off the top of my head.
Hope this helps.