Thanks for the reply.
I have not looked at this in a while, maybe I did not explain it clearly enough. I can change the rate per country configuration and this does flow through to the form. So for example, if I changed the config to 40%, 40% would print on the form. The problem is that it doesn't seem to have any bearing on the actual posting in FI. Unless I keep a value in the config from my screen shot above for With/tax rate the posting in FI does not work correctly.
I'll probably revisit this more closely in a few months and possibly send to SAP. We only had a small number of 1042's this past year and all were for the same rate so I was able to make it work.