You're working too hard at it. People will take it if they want to. Small cables won't discourage a prepared thief looking to score moto gear specifically. The others will just cut whatever with a knife to get to the hoped for goodies inside fast.
Don't leave valuables on the bike. Accept a certain amount of risk, but do what you can to mitigate it, like parking in view of where you will be, (restaurants).
I don't have locking mounts or lock my tank bag 99% of the time. There is nothing really valuable in there, all that goes in the jacket pockets, and the jacket comes with me, regardless of if it's a pita, unless I have an empty pannier to lock it in. And I do run hard bags. You've got more bulk in your forum profile pic that I run with hard luggage.
My wife and I have had our tank bags quickly gone thru. Likely the perp parked next to us in something large enough to hide his/her activities. Nothing taken, because nothing was there to take.
Sure, I'd be pissed if someone took the tank bag or helmet, (which I sometimes lock if we're going to be away for an extended period), but at the end of the day, if it's going to happen, it's going to happen.