I would like to discuss capillary tubes in regards to the following technical aspects:

1. Capillary tube size - diameter, length;
2. Refrigerant type;
3. Oil.

The technical aspects that come to mind are as follows (there will be many others):
a. Does each refrigerant have a certain cap tube 'sweet diameter'?
b. Cap tube noise levels;
c. Oil wetting, by refrigerant;
d. When does refrigerant plug-flow occur?
e. What size oil globule forms in each refrigerant (due wetting)?
f. How does the cap tube manage oil?

Basically, let's say, hypothetically, that you have a system that has been originally set up to use R-22 refrigerant. A new system is built, with compressor, filter-drier set up to use R-134a, but using the same diameter cap tube. What could reasonably be expected to happen?

If folks have practical experience in cap tubes, under different refrigerants & oils, I would very much like to hear your experiences.