Choosing mount size for future growth

[braxtonds]

This is my first post with a pic, I hope it works out.

I just received a shipment from Oak Hill Orchids, $10 for any mounted orchid special. They seemed alittle small for my preference but for the price and most importantly, for the species they had available, I am very pleased. These are my first mounts I've ever tried.

I received Bulbophyllum lobbii and Rhyncholaelia digbyana and both appear to be seedlings. I am very familiar with cattleyas, but this is my first bulbo. My question is the mounts are very small, should I consider transferring them to a new mount now, while they are attached but seemingly not permanently? Or should I wait until they are overgrown?

The website lists care instructions where it suggests that every 2 years you need to remount the orchids. I would prefer to choose a mount that will last much longer than that. Currently, the mounts are maybe 6-7" long slabs of wood and not very wide, what size should I choose for when I do need to remount?