I’m wondering if there’s a way to have an adjustable tolerance for this command so that when I select regions to CurveBoolean, that it will ‘jump the gaps’ in a similar way to how Illustrator can do this with the Paint Bucket tool?
No, I don’t think so. I think you need to have all the curves at least touching/crossing within the file absolute tolerance to be able to form closed regions. You could of course lower the tolerances temporarily to be bigger than the largest gap, but that’s playing with fire - first, you don’t know how exactly Rhino will connect those and second, if you forget to set it back to a correct tolerance later, you will likely create inaccurate geometry.
If I was to click within this region, CurveBoolean wouldn’t work because it’s not 100pc closed. But if there was a method like as is seen in illustrator’s gap options, it would likely be useful.
@jdelavaulx
You could try this script - it extends all selected open curves by a length (user input), if you give it a length more than the biggest gap, maybe it will create enough overlaps to close the figure afterward with CurveBoolean.