Thank you for information on hay bales! I've seen several techniques, and I like the look of your HO bales on Riverside, which I will try to replicate for my HO track.
These last days, I made some progress, I built and installed a laptiming computer (made from bits I always kept for DIY projects). Now I have to install the software (Race Coordinator) and the laptiming materials (arduino board, relay board). This is the final lap before I can enjoy this oval track !