I went with creating JavaScript functions that allow for me to specify % sizes, physical sizes, etc...:

Qt Code:
  1. //returns a density ratio of the current screen
  2. function appDensityRatio () {
  3. return appWin.appDensity / 11.6129; //appWin references the main window, and appDensity is set to Screen.pixelDensity
  4. }
  5.  
  6. // returns the pixels that equate to the provided inches
  7. function inchHeight(myInches){
  8. if( appDensityRatio() < 1.0 ) {
  9. if( appDensityRatio() >= 0.70 ) {
  10. return Math.round(myInches*(appWin.appDensity*25.4*appDensityRatio()));
  11. } else {
  12. return Math.round(myInches*(appWin.appDensity*25.4*0.70));
  13. }
  14. } else {
  15. return Math.round(myInches*(appWin.appDensity*25.4));
  16. }
  17. }
  18.  
  19. //returns a size as a percentage of the given size
  20. function psize(pcent,fullval){
  21. return pcent*(fullval/100)
  22. }
  23.  
  24. // returns the pixels that equate to the provided point size
  25. function pointHeight(myPoints){
  26. if( appDensityRatio() < 1.0 ) {
  27. if( appDensityRatio() >= 0.70 ) {
  28. return Math.round(myPoints*Math.round(appDensityRatio()*(appWin.appDensity*25.4)/72.0));
  29. } else {
  30. return Math.round(myPoints*Math.round(0.70*(appWin.appDensity*25.4)/72.0));
  31. }
  32. } else {
  33. return Math.round(myPoints*Math.round((appWin.appDensity*25.4)/72.0));
  34. }
  35. }
  36.  
  37. // returns the pixels that equate to the provided point size, used for FONTS only
  38. function fontHeight(myPoints){
  39. if( Math.round(appWin.appPixelRatio*fHeight()) < 1280 ) {
  40. return Math.round(myPoints * 0.75);
  41. } else {
  42. return myPoints;
  43. }
  44. }
To copy to clipboard, switch view to plain text mode 

Then I can set a size on the base window... and size everything on that size...
Qt Code:
  1. ApplicationWindow {
  2. id: main_window
  3. objectName: "main_window"
  4. x:0
  5. y:0
  6. width: Screen.width
  7. height: Screen.height
  8. }
To copy to clipboard, switch view to plain text mode 

Child windows are sized with
Qt Code:
  1. anchors.fill: parent
To copy to clipboard, switch view to plain text mode 
and all child window objects are sized to their parent with calls like so:
Qt Code:
  1. Rectangle { //Child Window (included in Main using a StackView)
  2. id: graphWindow
  3. border.color: "red"
  4. border.width: 2
  5. radius: 10
  6.  
  7. Rectangle { //Child object
  8. id: wspdChartRect
  9. color: appWin.rectBackColor
  10. anchors.left: parent.left
  11. anchors.leftMargin: Funcs.psize(1,graphWindow.width)
  12. anchors.right: parent.right
  13. anchors.rightMargin: Funcs.psize(1,graphWindow.width)
  14. anchors.top: parent.top
  15. anchors.topMargin: Funcs.psize(1,graphWindow.height)
  16. height: Funcs.psize(48,graphWindow.height)
  17. width: Funcs.psize(98,graphWindow.width)
  18. border.color: "red"
  19. border.width: 2
  20. radius: 10
  21. visible: true
  22. }
  23. }
To copy to clipboard, switch view to plain text mode