Ewa wrote yesterday:

Basically there are three crucial things to keep in mind when phonemicizing:

1. The “alphabet” is phonemic, so wherever a transcription deviates from the alphabet it is phonetic.

2. Raised vowels are schwas which are clearly phonetic in nature.

3. Schwas in general tend to be phonetic except for a few cases which are systematic. Only the latter kinds of schwas should be left in phonemic representations.