The assembly between the banisters and the handrail and also between the banisters and the stringboard can be adjusted to your preferences.
In both cases you are able to set a penetration depth.
There are 3 different options for the machining or chamfer associated with the penetration.
Perpendicular with 1 chamfer, where the banister penetrates on one side only.
Perpendicular with 2 chamfers, where the banister penetrates on both sides, this is the most common set up in stair building.
Vertical has no chamfer, this is commonly used for metal rods instead of banisters for example.
You can adjust all banisters at once, or select a single banister and edit just that.