Some drafters add (s) to the singular noun in order to ascertain that a given context may involve more than one of the given item. They add it to a verb as well, for obvious reasons. Avoid adding this (s) and everything that it triggers. If uncertainty (if any) needs to be addressed, provide in the interpretation article that:

References to words importing the singular shall include the plural and vice versa.

Alternative. If omitting the (s) truly entails an undesired uncertainty in a particular provision, use one or more.

No slash. Never use the slash (“ / ”), unless it is part of an existing name, trade mark or reference. Instead, use and or or (and respectively if applicable).