Don’t use the calculator, John is working on getting it upgraded… I am a master on US deaths, as Brek will attest.
Each kingdom has an inherent +- for that kingdom. Then you also have kingdom traits that will play into the success.
Ex: I have used the calculator for IL and SO on same encounter, one would be green across the other everything, except guarded attack is in danger. Both wizard kingdoms, same Power lvl wizards and leaders. Only difference is the inherited +- each kingdom has and what the actual defense classification of kingdom troops are. IMO also checked it with military kingdoms, same results, some have a better chance than others.
I once lost three leaders on a fine class: <.5% on each loss… killed my game..
Best case is to use the highest leaders possible guarded or mirror image(although a slight risk exist with this spell) and if possible don’t use the tac 3 option as it puts a greater risk on the death of companions. IMO
Shield isn’t a US option…use the spells under the US spell block..