Caturdaśī is to be taken when it continues up to midnight. If it is only upto the early part of the night and joined with another thereafter, it is also recommended.
Although I consider the phallic and the embodied form to be equal, the phallic form is excellent for those who worship. Hence for those who seek salvation the latter is preferable to the former.
The others too shall install the phallic form with Oṃkāra mantra and the embodied form with the five-syllabled mantra, with excellent articles of worship and adore with due homage.