Glad the information is useful. You are right about that technique being slow. It would be nice to have a single command to obtain that information but no such luck. Products have been struggling with this question for a long time. The EZSrve saves the Set MSB value of 0F or 3F which is all that is really necessary to access the link database. Powerhome2 has a user defined value in the GUI that can be adjusted as needed. The ISY determines the size once when an SHN device is added to the device inventory. Not too bad if it only needs to be done once.
Post again if we can add anything additional. The EZIOxx family of devices uses the same command set so what works for an EZIO2X4 also works for an EZIO8SA. Of course the number of Inputs and Outputs vary but the base command set is the same across the EZIOxx product line.