Few questions on handling nep cuttings

[alpiner]

1. Can you share your best way of handling odd form of mature plant from cutting, i.e. The cutting starts to shrink as plant grows bigger, giving imbalance look to the potting. Worse still, it starts to bend due to the added weigh from new plant. Right now I’m providing external supports, but that seems to be temporary as it will get worse over time. In addition, I may be wrong but I think it limits the stem of new plants from growing thicker too. That prevents me from trying out air layering method to induced roots directly above the cutting. Pls share if you’ve done that with success.
2. How deep do you normally pot your cutting, i.e. relatively from roots to bottom of pot? I learned from another experience CPer that the root of cutting should not be too close to the bottom, which makes sense.
3. Are roots going to be formed on the part of cutting buried in the media? I cut a slit on higher part of cutting on Glacilis and Amp, separated sliver with sphagnum moss, before covering everything but that may take some time before I dig up to make observation. Extracting too early I may just disturb the progress, and waste the effort.

Thanks in advance for your sharing.