Jeez. If you lived near Atlanta I'd invite you over.
Last timing chain I did, I rotated the engine like, 400 times manually to make sure that the engine marks and the chain marks were as close to each other as humanly possible across all cycles. I think it took between 70 and 90 rotations to line everything up on our little 2.7L tacoma.. It was really hard to pay attention for that long
It had a balance shaft chain to sync up as well..
The worst part is just getting the freaking cover siliconed back on. In our cars though, clearance would be a b*tch.
*As a person who used to work on $3,000,000 turbine-powered battle tanks, I can say with confidence that everyone f*cks up all the time at everything. If the timeline is *it worked, but needed a chain, then it got a chain and now has a new issue* then.. well. first try to clean out those sensors... but I'd brace for a redo.