For point [1] it's also trivial to file or Dremel the slot to be open-backed, if you're careful. I've done this successfully a handful of times, unsuccessfully a few more than that...
You could also use a razor blade or other such manual cutting devices...
(People are very very good with pretending at intelligence and bad at the practice of it)
Also don’t use a Dremel or even a file a hobby knife or flush cutters work just fine. If you have a steady hand then a hot knife attachment for a soldering iron is fine too. The cutting wheel on a dremel tool can run off and the dust it produces can be conductive and short something.