What is the recommened Simpson post base connector for attaching a 4 x 4 stair guardrail post to existing concrete slab?  Looking for something that will meet the code requirements for resisting lateral forces while providing a stand-off to keep the end grain isolated from the concrete.  Was looking at the ABU44Z, but a note says not recommended for non-top sopported posts.  Assuming that a guardrail does not qualify as ‘top supported.’

Thanks!