After burning up several transformers (due to a short in a valve), I switched to one of these: https://www.amazon.com/dp/B083R621RV. Overkill, for sure, and I fused the circuit to OS at 1 amp. I don’t know what the safe current for the OS module is. For the one situation in which I have more than two valves in a zone, I added a small relay that switches current from the same transformer, but fused at 4 amps.
Rog