I'm having trouble remembering when the primative for silver occurs in it's 5 stroke abbreviated form, and when it is the full 6 strokes.

The same problem with "good" too---closely related.

Anybody got a good idea about that?

The rule for how to write "silver" (goes for "good" and "eat" as well) is very straightforward:

When the primitive appears on the left, it is in its abbreviated form. In all other positions, the full form is used.

Thanks!