This must be your lucky day
I just called this morning, and got the part number for those threaded push rods. They are actually an RV-9 part, and are just a bit too long for the RV-8, so you'll have to trim them a bit.
The part number is VA-256, and you need two. Unfortunately, they're $12 each. I've threaded a handful of those aluminum tubes per the plans, and have never been entirely happy with the results, so I ordered some of these to see how they work.
Cheers,
Rusty