I have been very satisfied with the combination of a 5' tripod and 10' chain-link top rail. It forms a solid self supporting system that needs no guy wires. If service is needed, removal of one leg bolt allows the assembly to tilt over while secured to the roof by the two remaining bolts.
http://www.3starinc.com/tripod_mounts.html
http://www.homedepot.com/p/YARDGARD-...2#.UpuraCePU4w
That said, StephanieS is quite right, you should test the proposed site before committing to holes in the roof deck.
The 5016 is more directional than the antennas you tried previously. Therefor it provides better reception of signals it's aimed at, less reception of signals to the sides. Still, you have it, so try alternate locations and elevations.
Is there any chance the cable or matching transformer has a problem?