Is there a tehtar for the schwa sound? In Indonesian and Malaysian, the schwa /ə/ is an independent phoneme unlike in English where the schwa is a result of vowel reductions.

In the English Mode, it seems that an under dot is used for schwa but this leads to another problem.

I'm making a Tengwar Mode for Tagalog (I thought of making one for Indo and Malay as well), since Tagalog has a lot of A's, I decided to use the inherent vowel something where each tengwar has an inherent A with an under dot as a virama or vowel-killer. So now the schwa and virama share the same letter which is problematic.

I also want to make stress marks because stress is important in Tagalog. Should I just make my own tehtar for the schwa and stress?