Welcome aboard!
i make mine from stretched sprue.
take a scrap piece of your parts tree and hold it above a candle flame.
(not too low, you don't want to burn it. just let the rising heat do it's work)
rotate it with your fingers. when it begins to look glossy and soft,
pull your hands away from each other in a smooth motion.
the soft plastic will be drawn into a thin piece in the center.
with practice, you can make it turn out almost any diameter.
if you don't like the results try a few more and vary how far or how fast you pull the ends apart. don't bother trying to "re-stretch" stretched pieces. it does not work very well. (or go ahead and try; you'll see what i mean)
since the piece you made is the same styrene the kit is molded from, you can use the same paints and glue that you used on the kit.
and if your antenna ends up with a bit of sag after it's on, don't worry.
pass a flame under it until it sags a little, then leave it alone.
it will shrink up and pull tight.
the best thing about this technique is that each kit provides you w/ more sprue to practice with than you should need.
it's easier than it sounds, so give it a try.
good luck & welcome to the forum.
ed.