Starting with AC 10, we will use 'real' section markers.
When we started with AC 5.1, there were fixed section marker styles. (Like the fixed dimension ticks and arrowheads to this day.) We didn't like the available styles, so we adopted the policy of showing sections in plan with an object, independent of the SE cutting element. The independent object also means we can fudge the placement of the marker, rather than being bound to its actual extent. And we can have that two-headed marker option.
In 8 (I think), they instituted GDL section markers, so we can in principle make markers any way we want. In practice, scripting SE markers is rather quirky, and I decided to punt, waiting to see if it would improve.
The main disadvantage of the independent object is that you need a workaround to refer to the drawing in the set.
In 10, they have overhauled tweaked the reference method internally. It's mostly good, but the workaround linked above is actually made worse. I can't take it anymore.
And no, the scripting is still weird. In 10, SEs have visible hotspots that aren't detectable. Gimme a break. But on balance the time is now to switch to real sections.
Summary.
Object Pros: Total scripting control. Flexibility in graphic placement. Cons: Awkward drawing referencing. People think we're weird.
Real SE Pros: Unity. More intuitive, not fighting the program. Automatic referencing. Cons: Less graphic flexibility.
Standards and template updates are below the fold.
In previous templates, there were two main section marker layers. +Z S/E Tool is for the actual cutting elements. +Z SE & Detail Object is for the marker objects.
These layers will change in place, meaning their internal IDs are the same, don't worry about that.
SE elements that print go on +Z SE Print. These are typically the building sections and elevations, and the wall sections. If you need an object to represent a section, for whatever reason, you should also use this layer for the object. For printing SEs, use the marker Section Marker JM10.
Non-printing SE elements go on +Z SE Hide. These include the 'junk' working sections and the sections used to generate interior elevations. For these, use the marker Plain Section JAM9.
(I can't decide if there's any value in having a dedicated layer for IE sections.) (I also can't decide if there's any value in only showing IE sections on their home stories.)
In the templates, you have elevation and section markers which use Section Marker JM10, the presentable one, but they are all on the +Z SE Hide layer. Once the project progresses to where you want to show the markers, move them to the Print layer.