Is it considered bad design to support the bi-quad element on some kind of
stand-offs in 4 locations (2 per quad) between the element and the reflector?
Like nylon, possibly using a dab of epoxy to hold them in place?

In principle this ought to be OK. The presence of the standoff will
have some effect on the antenna's electrical behavior (increased
capacitance between element and the reflector) but I suspect that this
would probably be negligible in most cases. Depending on the
frequency in question, you might want to select a standoff material
which is known not to absorb RF at those frequencies. If you're
really feeling energetic, don't use nylon and epoxy - fabricate
standoffs out of Teflon, with a hole-and-slit arrangement to admit and
hold the antenna element, and a tapped hole in the base to allow it to
be secured to the reflector plate with a nonmetallic screw.

--
Dave Platt AE6EO
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