Bike security is not a one fit situation for all, in my opinion it must be related to what you are trying to secure. My primary concern is to deter the low level or opportunist from securing my possession. Ultimately what I am doing is buying time with any type of lock or security device. I want to delay the thief so that they are caught or damage the tools that they are using. A determined thief or professional is a different story, they have all of the time in the world and have substantial ability to deploy countermeasures to defeat any and all obstacles. With that being said i have some personal things that I do secure my bike.
1. Thou shall not use cable locks for primary or secondary security
2. Thou shall not use Kryptonite locks of any kind
3. Laclede 3/8" (10mm) Square "Lockdown" Security Chain w/ HARDNESS RATING OF 62-65 HRC. Can be ordered in custom lengths, i have couple at 2 foot lengths.
4. 2 different "Viro" shutter locks with 2 different keys. Benefit of using chain as protection against bolt cutters, hacksaw attack.
5. No less that 3/8" in chain size with the proper lock to fit. (who care about weight, that is what turbo on an ebike is for...)
6. Primary and secondary chains are case hardened and my tertiary cable is just for seat deterrent.
7. Time must be taken on how to secure a bike with chain. Due to tire size and frame geometry all chains will not fit, nor should they.
8. I have a special mini double saddle bag just to carry both locks and chains just behind the handlebar.
9. 4 minutes. That is my estimated time to delay a theft with me to be able to react with other countermeasures. Upon failure, insurance.