@ascentale @bobjonkman @bikenite A2. I think there's not a one size fits all recommendation. Depends on the bike frame geometry, what the cycle rack or other infrastructure you'd lock to where you're using it, your physical capabilities, and your resources for replacing the cycle should it get stolen.
For me, this meant getting very heavy Kryptonite and other motorcycle and construction equipment chains because I could not easily afford to replace my rides and because it is harder for someone with a portable angle grinder to manage holding the chain safely while cutting it. Because of inaccessible racks, I needed a LOT of meters of chain to have flexibility. It was heavy as shit and inconvenient, but less inconvenient than my ride being stolen.
I watched Lockpicking Lawyer videos and cycle vlogger videos to decide what to do & which brand/models to trust. Recently I came across this site as well:
https://www.bikelockwiki.com/ #BikeNite #CycleParkingAudit #UCAccessNow