I was able to reuse the same mount as for
my old ACK ELT. I had to bend the mount slightly to
keep the antenna from hitting the tubes on the seat
support, as the new antenna sits at an angle to the base.
I know that this location is far from optimal, as there
is no good ground plane. But, the RV-8 doesn't provide
any mounting locations that meet all the requirements
laid out in the ELT manual, as you well know.