someone had recommended clamping on to the seat with this Manfrotto Super Clamp 2915 w/out stud $24 :
add this Bogen 2918 standard stud w/ European Threading at top $5.95
and mount this Bogen 3369 extension arm $38 that goes up to 92 inches
Might need this Bogen 3103 adapter depending on what size threading you have:
or you can go with a roll of this to hide it from ushers:
just in case you didn't realize, I would never use duct tape. I have however used gaffers tape and have also used a couple of climbing belts that cinch tight to a pole once. It worked like a charm.