I know this isn't a good answer to your question, but I wanted to answer anyway in case it could be a tip to someone else reading this thread

I went and bought a Really Good U-shaped lock, the not-quite test winner but almost. Expensive, indestructible - and heavy. Great to have whenever I needed to lock my bike up somewhere nasty for a long time, like overnight, but otherwise just a pain in the behind to drag around.

So for all other purposes I bought a teensy lightweight pencilthin lock, and kept it around the stem and handlebars. Always there, always handy, and unnoticeable while riding. I used it for years, and never had anyone try to cut it.

My point is - unless you have a very desirable bike, you can often get away with a very skimpy lock, just so that bike thieves take the unlocked bike next to it instead. Locks aren't that easy to cut with regular tools, and if they have heavy duty tools they can cut almost anything anyway.

YMMV, of course.