As with repotting, mounting is generally best done as new roots are emerging. Older roots that have been used to life inside a pot don't always adjust well to a mounted life style. This said, mounting can be done at just about anytime ... during new root development (whenever that happens to be for the plant(s) in question) just is usually the most favorable time to do so.
Personally, I would recomend that you do NOT mount your entire collection. It would be depressing if you killed your entire collection. Rather, pick just three or so with which to experiment. Pick the plants you least care about or most easily replaced -- not your most expensive or favorite plants. If it turns out to be a disastrous expeiment, you have lost little in the way of plants. If instead it is a rip roarin' success, then you know you got it right and can proceed to start mounting others.
Keep in mind:
1) Not all plants -- even within a given genera -- might like being mounted under your conditions. (Again this is why it is better, IMO, to just do a few at a time. Makes it far easier to notice any issues that arise and deal with them.)
2) Mounted plants typically need watering FAR MORE frequently than potted ones. I do not know how humid or arid the Houston area is. RH is going to have a significant impact on the watering needs of any mounties.