hey HN do you know what SP of Selenicereus it is that you use for grafting and sent me a few cuttings of? those are going quite well mate.
i also have S. hamatus. it grows so fast sometimes sends out aerial roots. haven't tried it for grafting, but the stem form is fully sick fow show its got like these teeth things:
http://gardenbreizh.org/modules/pix/cache/photos_180000/GBPIX_photo_184329.jpg
KanJe, selenicereus are sort of like Hylocereus in that they are versatile and will grow just about anywhere. they are epiphytic and need heaps of water during the growing season. they grow fast, root easy as from cuttings and take up a bit of room but the flowers are epic.