Oncs Climbing out of pot

[Dragonflydanser]

Hi, we're kind of new to oncidiums, having started on Phals and Paphs, so if this is a naïve question, please: forgiveness.
We have three Oncidiums (Azumi, Pacific Matriarch and Jiaho Queen) and one Zygopetalum (Jumping Jack) that have been with us for a year or more, and all four are exhibiting the same behavior; that is, new pseudobulbs are climbing up on the shoulders of the older bulbs and will soon be looking precipitously over the edge of their pots. Repotting seems in order, but we are wondering, well, a few things.

1) is this normal and expected behavior?
2) how to repot? That is to say, should we cut off and dispose of the old bulbs or should we keep them?
3) if we keep the older bulbs, should they be buried in the medium so that the new growth is at soil level, or should the new growth be allowed to continue it's trip to the stars?

We have mounted the Jiaho Queen on a branch that, conveniently, has a crotch that veers off at almost exactly the angle that the bulbs are climbing. Any thoughts on that presentation would be appreciated. Is that appropriate, or should the Queen stay in potting medium?

I apologize if my thoughts are clumsy. Paphs are so much simpler to repot!

[Roberta]

Completely normal. Remember, in nature these tend to grow up the sides of trees. If the older pseudobulbs are firm, you should keep them - they are the "reserves" for the plant. You can partialy bury them. Mounting where you are accommodating the growth habit is great, your challenge will be to keep it damp enough. You can put sphagnum over the top of the roots to hold extra moisture (don't put the sphag between the roots and the mount if you want to give them a good chance to grab the mount)

[Dragonflydanser]

My thanks.