Depending on how you plan to draw the polygons, item values are most likely the simplest way to go. Using items as global variables shouldn’t really be the fallback plan, it should be the default plan unless there’s some significant reason not to. That’s really what items are.
The second-best approach is probably to use an oh-repeater. You can manually define a 1-element array of an object that contains all your values and then wrap the entire widget code in that repeater. Because it’s only one element it will only draw one iteration of your widget but the loop variable of the repeater will contain your values.