Salak can be planted out once it has 4-5 leaves. In nature it grows as an understory plant and likes shade. But, lots of shade is going to slow down development. Some farms limit shade completely and use lots of fertilizer, more sun more fertilizer.
We grow salak in light shade, you certainly see shadows. In our climate it can begin flowering in 3 years.
I have 3 species and 2 varieties of salacca salacca and the culture seems the same.
Peter