I would go with either the Sigelei Zmax v2.5 and purchase a provari pro ring ( they fit better on the zmax then on the provari itself ) and youll have yourself a flat top Zmax.. or if your into the telescopic thing ( i am not ) then get the new v3 telescopic flat top..
I have the 2.5 and use a proring to make it a flat top and it rocks, never had an issue.