Yes, me again.

Until my self-study kit comes in, I'm at the mercy of everyone here.

Null Driver setup:

I am assuming I would create this like I would for any other driver?

Create in the driver set
Add a filter on subscriber channel for what I want to abuse (User ->
password expiration time)

Since I'm going to change the value, I am assuming this would be a
command transform rule?

I can add a rule, but when the policybuilder comes up, there's no option
to insert a rule.

I can insert a pre-defined rule, but that's it.

The docs for 3.5.1 show me a nice (familiar) policy builder window but I
don't see those options

Can you not use the rule builder for Null Driver?