Christmas cactus (or any of the holiday cacti, for that matter) touchy??? Are we talking about the same plant(s)? I grow many Schlumbergera x buckleyi (Christmas Cactus) and Schlumbergera x truncata (Thanksgiving Cactus, often mistakenly called Christmas Cactus), and find them some of the easiest plants to grow that there is. Transplanting them should be very easy, and I doubt the process will even slow them down.

True Christmas Cactus does tend to be more weeping than most other holiday cacti. I doubt you could change this to any degree by doing anything at transplant. One thing you could try is keeping new growth in check by pinching/removing new segments while keeping the older segments supported until they are more mature (firmer). I've used bamboo skewers for this purpose with decent results. Another thing that helps is selective pruning. Removal of the more weeping growth and keeping the more upright growth can lead to a more upright plant.

Keep in mind that the plant's natural habit is weeping/low-growing, so you are fighting nature (an uphill climb) when trying to change that form significantly.

In agreement with brandon...these plants aren't fussy at all, and don't throw a fit when being repotted. Just be sure that you use a coarse textured potting mix. Don't go crazy about potting it in a huge pot, and be sure that it has adequate drainage holes. Though these plants are succulents and don't need to be watered all that often, it is important that you give them a good drenching on watering day. Little sips result in hard, dry pockets on soil and a lot of dead roots.

Just be sure that you use a coarse textured potting mix.

==>> that means.. if you want to buy a bag.. buy a cactus or orchid mix ... they tend to have big chunks of stuff to aerate the peat media ...

and i agree with brandon.. its a floppy plant.. and the only way to get it tall.. is to grow it so successfully.. that the flops start mounding on top of each other.. to get some overall height ...

your note made me go do mine ... as a fail safe.. i took the longest floppiest piece.. separated.. each segment.. and stuck them in another pot.. so just in case i fail ... i will have new rooting ...

i wanted to use the same pot.. so i took it to the hose.. and sprayed off about 1/2 of the old soil.. and put it back in the same pot.. with the new soil at the bottom and around the sides ...

ken