No recommended selector for multiple content projection slots in the styleguide

[joeeames]

The documentation & styleguide has no guidance for how to do a selector for multiple content projection slots. What is the "best practice" for selectors for multiple content projection?

Given the following:

...
</>

...
</>
and then in the projected component I would have:
<ng-content select="[my-title]" ...
<ng-content select="[my-body]" ....

But any selector can work. i.e. class selectors, given the right change to the HTML.
<ng-content select=".my-title" ...
<ng-content select=".my-body" ....

Or something else?

The styleguide should recommend a best practice.

@IgorMinar @wardbell @johnpapa