I am not sure why you chose Kings War rather than Unhappy King Charles, perhaps a factor of personal availability
Yes, entirely that.
Is it a straight replay of KW with tactical battles resolved on the tabletop?
Pretty much. I have made some very minor changes to accommodate the interface between the tabletop game and the board game and a some other minor changes to accommodate it being played solitaire.
I have only played POLEMOS once, long ago, and did not enjoy the experience so I cannot comment on your queries but do wonder why you have chosen to use them.
I like them in general – I play quite a lot of Polemos Napoleonics and Polemos SPQR too. I like lots of Phil Barker’s rules so I would be happy to give DBR a try, except that would require re-basing since I can’t think how I would use my existing combined pike and shot bases to play them. I can’t think of anything else out there that really appeals. I might get round to playing Basic Baroque, I guess. And that conversion of To the Strongest. Any other recommendations?