It doesn't work as far as I can tell, to just change the tccSite. Honeywell does not document this API. It's all been 'reverse engineered' and the same will have to be done for the international site.
I don't want to get too deep in munutia but as an example, the minimum number of cookies received from Honeywell US, is 8. For International, it's 4. In other words, the split is likely to get larger, not smaller. How to handle that falls to me, but without an international Thermostat to test, I can't get far.
Until this week, I only had one Thermostat. 
I certainly don't have more than one HVAC system, so a 2nd Thermostat couldn't be used. However, this week I upgraded my Thermostat to a RTH9585 and now have two registered Thermostats in the US. My thought is to take the old one and get it registered to International. (I tried it, but Honeywell's site rejected it saying it's already registered.) At this point it's not powered and I'll have to build a test jig to get it powered. Which is another way of saying, I can't fix it in a day.
If I make progress, I'll probably add to the existing topic which is more TCC (cloud) related than where this thread started (9000 series)
